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A171612 Integers n such that (25*10^n)+1 is prime. 0

%I #8 Jan 17 2019 13:44:08

%S 1,8,255,320,609,688,1436,3271,3921,6520,19604

%N Integers n such that (25*10^n)+1 is prime.

%C No others less than 20000.

%C See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "25001".

%H Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/">List of near-repdigit-related prime numbers</a>.

%H <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>.

%e For n=8 we have (25*10^8)+1 = 25*100000000+1 = 2500000000+1 = 2500000001, which is prime.

%Y Cf. A056797, A056804, A056805, A056806, A056807

%K more,nonn

%O 1,2

%A Julien Peter Benney (jpbenney(AT)ftml.net), Dec 13 2009

%E Edited by _Ray Chandler_, Dec 23 2010

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Last modified April 23 20:33 EDT 2024. Contains 371916 sequences. (Running on oeis4.)