20080930, 21:39  #1 
P90 years forever!
Aug 2002
Yeehaw, FL
7358_{10} Posts 
Odd email
I received this email today. The number is not prime, anyone have other ideas?
A senior ranking Non Commissioned Officer here in Iraq has given a group of us a number and no clues to as to what it is. A few of us feel it is something to do with it being a prime number. We are all not math geniuses. So here is where I turn to you for your expert opinion. The number is: 20120121122515626145776622735224615338815731191617 Please assist in any way you can. Thanks for your help. 
20080930, 21:43  #2 
Account Deleted
"Tim Sorbera"
Aug 2006
San Antonio, TX USA
10AB_{16} Posts 
BTW its factorization is:
20120121122515626145776622735224615338815731191617 = 479 * 133289810174980013 * 315136079611630044400219008571 Just from looking at the number I see it has a quite high number of pairs of digits (...1122...776622 etc.), but in a number of this length, that could be purely coincidental. 
20081001, 03:52  #3 
Oct 2006
2^{2}×5×13 Posts 
Well, looking at it as a substitution cipher, I get the possibilities:
Code:
20120 tat 1211225 lkve lkby laly lalbe laave auly auve abkve abkbe abaly abaave abalbe 15 o ae 6 f 26 z bf 14 n ad 5 e 7 g 7 g 6 f 22 v bb 7 g 3 c 5 e 224 vd bx bbd 6 f 15 o ae 3 c 3 c 8 h 8 h 15 o ae 7 g 3 c 119 ki 16 p af 17 q ag I initially thought it could be a cipher because of the many strings of 2x and 1x in the first half. Within the number, only 2012012112251562614577662273522461533881 120121122515626145776622735224615338815731191617 6145776622735224615338815731191617 617 17 7 are prime (working from the beginning to end or vice versa, deleting one digit at a time). This is quite a bit lower than most that I've seen (ie from the Homeprime patterns). I don't know if this is helpful at all, but good luck with it 
20081001, 22:58  #4  
Cranksta Rap Ayatollah
Jul 2003
641 Posts 
Quote:
50 digit number has 49 pairs of digits, the probability that a pair of digits is comprised of the same digit is 10%, so we expect to see about 5 pairs (which includes something like ...12223... counting as 2 pairs). I count 9 pairs, which is 1.95 standard deviations away (using the binomial distribution), and I think that's right under the 95% confidence interval, so I'd say it's not extraordinary, but I wouldn't be surprised if someone else came along and told me I was wrong 

20081102, 15:55  #5 
I quite division it
"Chris"
Feb 2005
England
31×67 Posts 
Okay, I give up.

20081117, 18:44  #6  
Feb 2007
432_{10} Posts 
Quote:
Code:
? [20,12,01,21,12,25,15,6,26,14,5,7,7,6,6,22,7,3,5,22,4,6,15,3,3,8,8,15,7,3,11,9,16,17] ? Strchr(Vecsmall(%+vector(#%,i,64))) "TLAULYOFZNEGGFFVGCEVDFOCCHHOGCKIPQ" /*pasted into rot13 */ GYNHYLBSMARTTSSITPRIQSBPPUUBTPXVCD PS: I used the "maximum munch principle" for putting the commas, but maybe military people are less scientific and some other splitting up was intended  I didn't check if something more reasonable can be obtained. PPS: first I was intrigued by the repetition at the beginning and tried direct ascii conversion using maximum munch principle: 201,201,211,225,156,... but this gives nothing afaics ; b.t.w. it is improbable that the message starts with 2 repeated letters (unless it is to be read from right to left). Last fiddled with by m_f_h on 20081117 at 18:53 

20081118, 12:22  #7 
Jun 2005
101110101_{2} Posts 
The other question is: Do we really want to help officers in Iraq, commissioned or not, help doing their work? I would not, even if I was not too lazy to think about puzzles with no clue whatsoever.
Oops, did I just annihilate my chance of ever getting a visa for the States? H. 
20081119, 03:56  #8  
Cranksta Rap Ayatollah
Jul 2003
641 Posts 
Quote:
29 different five letter sequences (incorrectly assuming independence), roughly 8600 5 letter words in the English language, the chances of NONE of the sequences containing a word is (18600/26^5)^29 ...so about 1 out of 50. (if you don't like my independence assumption, we can take the 7 different blocks of letters that don't interact for a lower bound. That gives us about 1 out of 200) Last fiddled with by Orgasmic Troll on 20081119 at 03:59 

20081121, 16:10  #9 
Nov 2008
2×3^{3}×43 Posts 
A possible clue:
The first 11 digits are all 0, 1 or 2. Digit counts: 0 appears 2 times 1 appears 12 times 2 appears 10 times 3 appears 4 times 4 appears 2 times 5 appears 6 times 6 appears 6 times 7 appears 5 times 8 appears 2 times 9 appears 1 time There is a rather uneven distribution of digits, and most digits appear an even number of times. Of course all of this could be chance... Last fiddled with by 10metreh on 20081121 at 16:21 
20081121, 17:49  #10 
Aug 2008
2×43 Posts 
A) Since there are 50 digits, I spread them out in rows of 5:
Code:
A) B) C) 2 0 1 2 0 VA 2 0 1 2 0 1 2 1 1 2 NY 1     2 5 1 5 6 WV 2     2 6 1 4 5 WV 2     7 7 6 6 2 TX 7     2 7 3 5 2 NC 2     2 4 6 1 5 VA 2     3 3 8 8 1 FL 3     5 7 3 1 1 SD 5 7 3 1 1 9 1 6 1 7 CA 9 1 6 1 7 C) I fed them into a zip code lookup function, forwards, backwords, down, and up, but only found 5 valid codes (out of 40): Forwards: 20120 ... ... Sully Station:Fairfax:VA 57311 ... ... Farmer:Hanson:SD 91617 ... ... Valley Village:Los Angeles:CA Backwords: nothing Down: 21227 ... ... Baltimore:Baltimore:MD Up: 95322 ... ... Santa Nella:Merced:CA Diagonals: nothing I found it really peculiar that the only digits that made valid zip codes were along the top, left, and bottom of my chart. I'm sure it's just coincidence though. I don't have any more zip code ideas. I'm posting here to possibly spur someone else on Last fiddled with by uigrad on 20081121 at 17:55 Reason: typo 
20081125, 22:33  #11 
Jan 2005
Caught in a sieve
5×79 Posts 
It's kind of odd that the number starts with a 2, then two entries of 012.
I wonder if somebody left out some character code indicator, e.g.: 2 0x12 0x12 1122515626145776622735224615338815731191617 Now, 12 could be a form feed character; or it could be the size of something. Removed speculation that didn't add up... OK, I give up for now. Last fiddled with by Ken_g6 on 20081125 at 22:38 Reason: Removed speculation that didn't add up... 
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