A159265 - OEIS

%I #14 Apr 03 2023 10:36:11

%S 379009,379000009,37900000009,379000000009,

%T 3790000000000000000000000000000000000009,

%U 37900000000000000000000000000000000000000000009,3790000000000000000000000000000000000000000000000000000000000000000009

%N Google primes: primes of the form 379*10^n+9 = 3790...09.

%C The prime number 379009 rotated by 180 degree reads "GOOGLE". This sequence gives primes of this form with a string of 0's of arbitrary length, as it appears (upside down) on the web site of the search engine to browse the pages of available search results.

%D J. Earls, Mathematical Bliss, Pleroma Publications, 2009, pages 15-17. ASIN: B002ACVZ6O [From _Jason Earls_, Nov 21 2009]

%H G. L. Honaker, Jr. and Chris Caldwell, <a href="https://t5k.org/curios/cpage/11196.html">Prime Curios! 379009</a>

%F a(n) = 379*10^A159264(n)+9.

%t Select[Table[379*10^n + 9, {n, 3, 70}], PrimeQ] (* _Arkadiusz Wesolowski_, Oct 05 2011 *)

%o (PARI) for( n=0,99, ispseudoprime(379*10^n+9) & print1(379*10^n+9,","))

%K nonn,word

%O 1,1

%A _M. F. Hasler_, Apr 07 2009