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 A239792 #14 Jun 28 2019 07:14:48 %S A239792 1,-1,3,-61,1261,-4977,999645,-16820653,288427601,-1975649524361, %T A239792 250373334235999,-741069328361243,2017175162278526957, %U A239792 -16484758150014378103,1866091048556360006871,-747145289541069391049541,558035966935526487401599645,-94004035636878314426017611 %N A239792 Numerator of b_{2n}(1/4), where b_{n}(x) are Nörlund's generalized Bernoulli polynomials. %D A239792 Y. L. Luke, The Special Functions and their Approximations, Vol. 1. Academic Press, 1969, page 34. %D A239792 N. E. Nörlund, Vorlesungen über Differenzenrechnung, Berlin, 1924. %H A239792 J. L. Fields, <a href="http://dx.doi.org/10.1017/S0013091500013171">A note on the asymptotic expansion of a ratio of gamma functions</a>, Proc. Edinburgh Math. Soc. 15 (1) (1966), 43-45. %F A239792 Let b(n) = -Sum_{k=2..n} (C(n-1, k-1)*Bernoulli(k)*b(n-k)/k)/2 for n>0 and otherwise 1. Then a(n) = numerator(b(2*n)). %p A239792 b := proc(n) option remember; if n < 1 then 1 else %p A239792 -add(binomial(n-1, k-1)*bernoulli(k)*b(n-k)/k, k= 2..n)/2 fi end: %p A239792 A239792 := n -> numer(b(2*n)); %p A239792 seq(A239792(n), n=0..17); %t A239792 b[n_] := b[n] = If[n < 1, 1, -Sum[Binomial[n - 1, k - 1] BernoulliB[k] b[n - k]/k, {k, 2, n}]/2]; %t A239792 a[n_] := b[2n] // Numerator; %t A239792 Table[a[n], {n, 0, 17}] (* _Jean-François Alcover_, Jun 28 2019, from Maple *) %Y A239792 Cf. A220412, A239793 (denominators). %K A239792 sign,frac %O A239792 0,3 %A A239792 _Peter Luschny_, Mar 26 2014