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 A337430 #5 Sep 25 2020 00:00:01 %S A337430 2,4,6,8,10,11,12,15,16,18,20,21,22,23,24,25,28,29,30,32,36,38,39,40, %T A337430 41,42,43,44,45,47,48,50,52,53,54,55,56,57,58,60,63,64,66,67,68,70,71, %U A337430 72,73,75,76,79,80,81,84,85,87,88,90,91,92,94,95,96,98,99,100 %N A337430 Numbers k such that the largest prime factor of 2^k - 1 is less than the largest prime factor of 2^k + 1. %o A337430 (PARI) for(n=2,100,my(p=vecmax(factor(2^n-1)[,1]),q=vecmax(factor(2^n+1)[,1]));if(p<q,print1(n,", "))) %Y A337430 Cf. A002587, A005420, A337431 (complement). %K A337430 nonn %O A337430 1,1 %A A337430 _Hugo Pfoertner_, Sep 23 2020