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%I #11 May 03 2024 12:40:53
%S 1,8,255,320,609,688,1436,3271,3921,6520,19604,38348,63531
%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
%E a(12)-a(13) from Kamada data by _Tyler Busby_, May 03 2024