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 A098242 #12 Aug 31 2024 04:25:30 %S A098242 12,24,37,60,62,84,87,112,122,137,144,162,171,180,181,187,212,237,253, %T A098242 262,264,269,287,312,318,337,362,387,412,416,420,422,423,433,437,462, %U A098242 465,480,487,512,537,541,544,562,563,587,591,612,637,662,665,684,687 %N A098242 Numbers k such that gcd(2k+1, numerator(Bernoulli(4k+2))) is not squarefree. %H A098242 Amiram Eldar, <a href="/A098242/b098242.txt">Table of n, a(n) for n = 1..1000</a> %t A098242 Select[Range[700], !SquareFreeQ[GCD[2*# + 1, BernoulliB[4*# + 2]]] &] (* _Amiram Eldar_, Aug 31 2024 *) %o A098242 (PARI) for(n=1,3000,if(!issquarefree(gcd(2*n+1,numerator(bernfrac(4*n+2)))),print1(n","))) %Y A098242 Complement of A098240. %Y A098242 Cf. A013929, A027641, A027642, A067778, A097704. %K A098242 nonn %O A098242 1,1 %A A098242 _Ralf Stephan_, Sep 01 2004