This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A171612 #11 May 03 2024 12:40:53 %S A171612 1,8,255,320,609,688,1436,3271,3921,6520,19604,38348,63531 %N A171612 Integers n such that (25*10^n)+1 is prime. %C A171612 No others less than 20000. %C A171612 See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "25001". %H A171612 Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/">List of near-repdigit-related prime numbers</a>. %H A171612 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>. %e A171612 For n=8 we have (25*10^8)+1 = 25*100000000+1 = 2500000000+1 = 2500000001, which is prime. %Y A171612 Cf. A056797, A056804, A056805, A056806, A056807 %K A171612 more,nonn %O A171612 1,2 %A A171612 Julien Peter Benney (jpbenney(AT)ftml.net), Dec 13 2009 %E A171612 Edited by _Ray Chandler_, Dec 23 2010 %E A171612 a(12)-a(13) from Kamada data by _Tyler Busby_, May 03 2024