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Old 2008-10-26, 10:24   #4
Oleg V.Cat
 
Oct 2008
Riga, Latvia

1110 Posts
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Hmmm...

Loks like that are just two 10 digits prime numbers, which are under the following rules:

First digit is a prime.
First 2 digits form a prime
...
First n-1 digits form a prime.

Numbers are:
1979339333
1979339339

If we need 11 digits number, then we must use 10, 40 or 82 as first two digits (so, only 3,4,5...10 first digits form a prime), full result set with 11 and more digits is:
10399793993
40993391939
82939939933
103997939939
409933919393
829399399331
829399399333
4099339193933

Intresting, that digits "1" and "7" are rare, average probability for all 4 possible digits (1,3,7,9) must be 0.25, but we have only 0.025 for "7" and 0.05 for "1".
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