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#21403 - Fri Nov 03 2000 03:09 AM Primes...again!
Thiv Offline
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Registered: Fri Nov 19 1999
Posts: 1377
Loc: Canada
1-What is unusual about the prime 73939133?
Gtho4 answered CORRECTLY

2-Each letter stands for a different digit.

AGCC
ABFC
GDDA
CEAG

Not only are the numbers across, down and diagonal primes,
but also across-backwards, up from bottom and diagonal from the bottom!
Karmaloupster answered CORRECTLY

3-Build a PENTAGRAM, at each point and intersection
there will be a prime number. The sum of each straight line will be 84

4-How many times a day does a prime number appear on your digital clock?
(24:00 format)
Gtho4 answered 210, my answer 211

5-Why is PRIME a prime?
Karmaloupster answered CORRECTLY

[This message has been edited by Thiv (edited 11-04-2000).]

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#21404 - Fri Nov 03 2000 03:24 AM Re: Primes...again!
gtho4 Offline
Administrator

Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder
73939133

take a digit off the back end of this eight digit number, and you still have a prime etc etc

7 digit 7393913
6 digit 739391
...
2 digit 73
1 digit 7

Thiv, welcome home, again - will get back to you on the rest
seem to be getting a nose bleed thinking about them


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#21405 - Sat Nov 04 2000 12:27 AM Re: Primes...again!
hundredaire Offline
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Registered: Tue Aug 29 2000
Posts: 422
Loc: Hell Michigan USA
4-How many times a day does a prime number appear on your digital clock (24:00 format)?

204


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#21406 - Fri Nov 03 2000 01:23 PM Re: Primes...again!
Anonymous
No longer registered


5- Why is PRIME a prime?


When you correspond each letter in PRIME to a number in the alaphabet starting at A=1, then the resulting sum of all the letters in PRIME is

16 + 18 + 9 + 13 + 5 = 61.... which of course is itself a prime.

------------------
If all the worlds wealth were divided between every man, woman & child
presently alive on the planet, we would all have $13 million a piece.
**************************************************

$13 Million for every single Human....
**************************************************


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#21407 - Fri Nov 03 2000 03:50 PM Re: Primes...again!
Thiv Offline
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Registered: Fri Nov 19 1999
Posts: 1377
Loc: Canada
G and Karma are correct!

H, I have a different answer but you're not too far off!

[This message has been edited by Thiv (edited 11-03-2000).]

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#21408 - Fri Nov 03 2000 08:00 PM Re: Primes...again!
hundredaire Offline
Enthusiast

Registered: Tue Aug 29 2000
Posts: 422
Loc: Hell Michigan USA
4-How many times a day does a prime number appear on your digital clock (24:00 format)?

194


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#21409 - Sat Nov 04 2000 12:02 AM Re: Primes...again!
Thiv Offline
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Registered: Fri Nov 19 1999
Posts: 1377
Loc: Canada
Hundredaire,
You're getting colder!
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#21410 - Sat Nov 04 2000 02:19 AM Re: Primes...again!
gtho4 Offline
Administrator

Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder
on a 24hr digital clock from 00:00 to 23:59

210


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#21411 - Sat Nov 04 2000 02:29 AM Re: Primes...again!
Anonymous
No longer registered


Ok...

#2...

2-Each letter stands for a different digit.

AGCC
ABFC
GDDA
CEAG

Not only are the numbers across, down and diagonal primes,
but also across-backwards, up from bottom and diagonal from the bottom


Answer : The correct numbers (I think) are:


1 9 3 3
1 2 8 3
9 5 5 1
3 7 1 9

making: A= 1
B= 2
C= 3
D= 5
E = 7
F = 8
G = 9


Nice quiz...

Next... #4

4-How many times a day does a prime number appear on your digital clock (24:00 format)?


Answer: 217 times per day.

------------------
If all the worlds wealth were divided between every man, woman & child
presently alive on the planet, we would all have $13 million a piece.
**************************************************

$13 Million for every single Human....
**************************************************


Top
#21412 - Sat Nov 04 2000 02:40 AM Re: Primes...again!
Thiv Offline
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Registered: Fri Nov 19 1999
Posts: 1377
Loc: Canada
CORRECT on #2 Karmaloupster!

G, I have 211 so I'll give you an Honourable mention!

Still waiting for the pentagram!

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#21413 - Sat Nov 04 2000 03:31 AM Re: Primes...again!
gtho4 Offline
Administrator

Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder
2.

this is a close as I can get as I'm losing too much blood, there are 20 numbers and 17 are primes, 3 aren't" 3283 (diagonal bottom LH top RH cnr) 9427 (2nd col from leeeft, going down) 3841 (2nd row from top, going backwards right to left)

1933
1483
9221
3719

3.

a pentagram - a five pointed star drawn with 5 straight lines, in one continuous stroke, each straight line having four intersections/points - so every line has 4 primes which add to 84, if I've got you right Thiv there's no way I can draw this ..

a 5 pointed star has an apex at the top AP, two points at the bottom - one at bottom left BL and one at bottome right BR, a left point LP, and a right point RP ... trying this clockwise from the top

AP 13
RP 43
BR 41
BL 17
LP 7

the line from the left point LP to the right point RP has 23 and 11 in the middle at the two intersections - so that line reads 7 23 11 43 left to right

the (almost) vertical line from apex AP to the bottom left point BL has 23 and 31 in the middle at the intersections - so that line reads 13 23 31 17 top to bottom

the other (almost) vertical line from apex AP to the bottom right point BR has 11 and 19 in the middle - so that line reads 13 11 19 41 top to bottom


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#21414 - Sat Nov 04 2000 03:36 AM Re: Primes...again!
gtho4 Offline
Administrator

Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder
oi! I've been punching away for an hour and KL solved it
blood was lost unnecessarily lol

re 210, do you want me to list them! I counted them 5 times (notice it's not an even number0

ok you two, here's an easy one ... what is the highest 3 digit prime? call it KLM .. what is the KLMth prime?


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#21415 - Sat Nov 04 2000 03:50 AM Re: Primes...again!
gtho4 Offline
Administrator

Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder
Thiv, one thousand apologies, just counted them again (that makes six, five re-counts .. sounds like scrutineers at an election) and there are indeed 211 and not 210, sorry mate

my error was in 1800 to 1859, my original count and four re-counts had 4 primes, when everyone knows there are 5 primes in that hour


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#21416 - Sat Nov 04 2000 03:53 AM Re: Primes...again!
Anonymous
No longer registered


hey Gt...sorry bout that believe me it was drawing blood here too..been on it all day..lol..not sure what I am being suckered here with but it is with trepidation that I post the "KLM" th prime number as 997 pr aare you after three-digit # with three differen digits, ie "K .. L....M...", then it is 983.

have I fallen for something here GT?

------------------
If all the worlds wealth were divided between every man, woman & child
presently alive on the planet, we would all have $13 million a piece.
**************************************************

$13 Million for every single Human....
**************************************************


Top
#21417 - Sat Nov 04 2000 07:13 AM Re: Primes...again!
gtho4 Offline
Administrator

Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder
ok, you're half-way there - what is the 997th prime number
e.g. the 25th prime number is 97

you know I went and checked your box of numbers and damn, it cross added correctly, so I pulled all the scraps out of the garbage bin and found my workings which had your / Thiv's numbers, and I marked that one as no go, and moved onward .. der!
if you want some more primes go back in the archives to earlier in the year, Thiv posted some doozies


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#21418 - Sat Nov 04 2000 09:15 AM Re: Primes...again!
Anonymous
No longer registered


lol gtho know what you mean...i only saved a qurater of a ream when I stopped trying to "palindromise" each one before accepting it or tossing it out....once i found out that there were no such beasts as 4 digit prime #'s.. (ie 7887 is not prime, must have five..like 10301)....you know damn well gt that i'll be chasing down ya' insignificant 997th prime # even if i have to work it out manually..lol...so i have answer I hope...

the 997th prime # = 7883

if the next step is the 7883rd Prime then I have got that one...if it is not the step and I have presumed hastily feel well in the knowledge that i wasted my time learning about Primes..lol..ok here is the 7883rd..


the 997th prime # = 80429 ( i think)

and i'm stopping here and hoping...
here's one to chase if u and everyone else would like, it's probably something that everybody already knows or have come across ....


What is the only number which is palidrominc and prime and has an even number of digits?

Easy one

------------------
If all the worlds wealth were divided between every man, woman & child
presently alive on the planet, we would all have $13 million a piece.
**************************************************

$13 Million for every single Human....
**************************************************


Top
#21419 - Sat Nov 04 2000 08:10 PM Re: Primes...again!
Thiv Offline
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Registered: Fri Nov 19 1999
Posts: 1377
Loc: Canada
My apologies!
By PENTAGRAM I meant a 5-pointed STAR...
(do not link corners directly)

Wanna try a cube, anyone?
This time I'll be SPECIFIC, count only TWO ADJACENT CORNERS! that total to a prime number(numbers 0-7)

as for

What is the only number which is palidrominc and prime and has an even number of digits?

...will get back to you!
My guess is G will get it first!

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#21420 - Sat Nov 04 2000 09:03 PM Re: Primes...again!
gtho4 Offline
Administrator

Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder
Thiv,

I don't think there is one .. when looking at primes doing your Q2 none of the 4 digit primes were palindromes. Your 2nd bottom row was GDDA so I looked at all the 4 digit primes with double middles .. and for the last ten minutes I've been doing a few divisions long-hand (can't find a darn calculator!), and every 4 digit palindrome I've written down, prime or not, was divisible by 11 - remember reading that somewhere. Every 2 digit number which is a palindrome is divisible by 11, add on another 2 digits then that 4 digit number is (should?) also be divisible by 11. I don't remember calculus and theroems from school as it's now too far back, to +vely prove this, altho it sounds logical! lol .. ok, found a calculator - and every 4 digit and 6 digit prime I've tried is divisible by 11, ditto a couple of 8 digit ones I've tried. Have found odd digit numbers which are primes, but no even digit primes.

Let's wait till KL gets back in here and we'll see if he's pulling our leg and/or sending us on a wild goose chase .. if there is one (which I now doubt) it can only begin with 1 3 7 or 9 .. here are some odd digit primes which are palindromes, there are 15 of them under 1,000

101
131
151
181
191
313
353
373
383
727
757
787
797
919
929

~~~~~~~~~~~~~~~~~~

re the numbers and star posted above - I didn't join the corners of the five pointed star, did I?! e the cube, what do the two adjacent corners add to - anything - so long as it's a prime - yes?


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#21421 - Sat Nov 04 2000 11:18 PM Re: Primes...again!
gtho4 Offline
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Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder

eleven


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#21422 - Sat Nov 04 2000 11:58 PM Re: Primes...again!
Thiv Offline
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Registered: Fri Nov 19 1999
Posts: 1377
Loc: Canada
Re: Cube
The two adjacent corners must be a single digit (0-7) AND
total to a prime number!

Re: Pentagram
Give up?

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#21423 - Sun Nov 05 2000 12:18 AM Re: Primes...again!
Anonymous
No longer registered


GTHO is correct with the only even prime, 11. Wild gooose chase indeed..lol.

Thiv I'll have a crack at the Pentagram and get back to you.


------------------
If all the worlds wealth were divided between every man, woman & child
presently alive on the planet, we would all have $13 million a piece.
**************************************************

$13 Million for every single Human....
**************************************************


Top
#21424 - Sun Nov 05 2000 01:39 AM Re: Primes...again!
gtho4 Offline
Administrator

Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder
cube is lying down facing us

sequence:- clockwise beginning at top LH corner, then top RH corner, bottom RH corner and finishing at bottom LH corner ...

1 4 7 6 the face we're looking at
rotate the cube clockwise
4 3 0 7 is what we're now looking at
rotate the cube clockwise again
3 2 5 0 is what we're now looking at
and one more time
2 1 6 5 is the last face we're looking at

now back to the start, these are the adjoining corners:
1+4=5
4+7=11
7+6=13
6+1=7
rotate the cube again clockwise, these are the corners:
4+3=7
3+0=3
0+7=7
7+4=11
rotate the cube clockwise again, these are the corners:
3+2+5
2+5=7
5+0=5
0+3=3
and the last face
2+1=3
1+6=7
6+5=11
5+2=7
this rotation sequence has also covered the face on which the cube is lying (can't see it!) and the face on top which is facing up .. if this still makes no sense, go ahead .. make my day, shoot me


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#21425 - Sun Nov 05 2000 02:01 AM Re: Primes...again!
gtho4 Offline
Administrator

Registered: Sun Dec 26 1999
Posts: 53998
Loc: Sydney
oz downunder
there's noway I'm gonna explain or draw this pentagram so we both get on the same wavelength .. there's a drawing of a pentagram at http://celt.drak.net/alliekat/images/pentelem.gif which I won't copy into here as that page is copyright as per the main page http://www.celt.drak.net/alliekat/pentagram.htm

anyway, using that drawing as a reference point this is what all the abbreviations in the post above mean:-

AP 13 ... spirit .. apex on that web page
RP 43 ... water .. the Right Point
BR 41 ... fire ..... the Bottom Right point
BL 17 ... earth .... the Bottom Left point
LP 7 .... air .... the Left Point

13 23 31 17 ... the line spirit->earth
13 11 19 41 ... the line spirit->fire
7 23 11 43 ... the horizontal line air->water
7 31 5 41 .... the line air->fire
43 19 5 17 .... the line water->earth


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#21426 - Sun Nov 05 2000 02:23 AM Re: Primes...again!
Thiv Offline
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Registered: Fri Nov 19 1999
Posts: 1377
Loc: Canada
No problem, eh?

WTG, G!

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Thiv

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#21427 - Sun Nov 05 2000 04:41 AM Re: Primes...again!
Anonymous
No longer registered


Well done GTHO.

------------------
If all the worlds wealth were divided between every man, woman & child
presently alive on the planet, we would all have $13 million a piece.
**************************************************

$13 Million for every single Human....
**************************************************


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