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 A273814 #14 Nov 12 2024 14:32:02 %S A273814 2,3,7,13,47,89,139,523,1051 %N A273814 Numbers k such that (12^k - 7^k)/5 is prime. %C A273814 All terms are prime. %C A273814 The corresponding primes are 19, 277, 7001653, 21379263273733, 105329145253605843602014309589572596276217801876213, ... %C A273814 a(10) > 50000. - _Michael S. Branicky_, Nov 12 2024 %p A273814 A273814:=n->`if`(isprime((12^n - 7^n)/5), n, NULL): seq(A273814(n), n=1..10^3); # _Wesley Ivan Hurt_, Jun 01 2016 %t A273814 Select[Range[1, 10000], PrimeQ[(12^# - 7^#)/5] &] %o A273814 (PARI) for(n=1, 10000, if(isprime((12^n - 7^n)/5), print1(n, ", "))) %Y A273814 Cf. A004064, A062578, A128348. %K A273814 nonn,more,hard %O A273814 1,1 %A A273814 _Tim Johannes Ohrtmann_, May 31 2016