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 A098240 #17 Aug 31 2024 04:26:37 %S A098240 1,2,3,4,5,6,7,8,9,10,11,13,14,15,16,17,18,19,20,21,22,23,25,26,27,28, %T A098240 29,30,31,32,33,34,35,36,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52, %U A098240 53,54,55,56,57,58,59,61,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77 %N A098240 Numbers k such that gcd(2k+1, numerator(Bernoulli(4k+2))) is squarefree. %H A098240 Amiram Eldar, <a href="/A098240/b098240.txt">Table of n, a(n) for n = 1..10000</a> %t A098240 Select[Range[80],SquareFreeQ[GCD[2#+1,BernoulliB[4#+2]]]&] (* _Harvey P. Dale_, Jul 23 2013 *) %o A098240 (PARI) for(n=1, 3000, if(issquarefree(gcd(2*n+1, numerator(bernfrac(4*n+2)))), print1(n", "))) \\ Herman Jamke (hermanjamke(AT)fastmail.fm), Nov 02 2006 %Y A098240 Complement of A098242. %Y A098240 Cf. A005117, A027641, A027642. %K A098240 nonn %O A098240 1,2 %A A098240 _Ralf Stephan_, Sep 01 2004