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 A306745 #14 Mar 08 2019 03:27:44 %S A306745 1,2,6,6,10,6,210,2,30,210,110,30,546,14,30,462,1190,6,51870,70,2310, %T A306745 2310,322,210,6630,286,330,798,290,30,930930,1430,1122,82110,70,330, %U A306745 21111090,38038,390,210,536690,39270,7489482,10010,62790,4470510,687610,462 %N A306745 Even bisection of A318256. %C A306745 The ratio sequence of a(n)/A006955(n) begins: 1,1,1,1,1,1,1,1,1,5,1,5,1,7,1,1,7,1,1,35, ... %C A306745 This divisibility by A006955 was confirmed by _Peter Luschny_ in the SeqFan mailing list. %H A306745 Jean-François Alcover, <a href="/A306745/b306745.txt">Table of n, a(n) for n = 0..1000</a> %F A306745 a(n) = (denominator of B(2n,x)) / (the squarefree kernel of 2n+1), where B(2n,x) is the 2n-th Bernoulli polynomial. %t A306745 sfk[n_] := Times @@ FactorInteger[n][[All, 1]]; %t A306745 a[n_] := (BernoulliB[2 n, x] // Together // Denominator)/sfk[2 n + 1]; %t A306745 Table[a[n], {n, 0, 60}] %Y A306745 Cf. A006955, A318256. %K A306745 nonn %O A306745 0,2 %A A306745 _Jean-François Alcover_ and _Paul Curtz_, Mar 07 2019