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 A321330 #9 Nov 16 2018 04:54:06
%S A321330 2,4,1,80,1,1120,1,44800,1,197120,1,1793792000,1,102502400,1,
%T A321330 4879114240000,1,259568877568000,1,40789395046400000,1,
%U A321330 238803367362560000,1,9561686829196902400000,1,1050734816395264000000,1,7922540515620290560000000,1,52951091790199773986816000000
%N A321330 Denominators of a Boas-Buck sequence for the triangular Sheffer matrix S2[3,1] = A282629.
%C A321330 The numerators are given A321329.
%C A321330 For the rationals beta see the example in A321329. The sequence alpha = {1, repeat(0)}.
%C A321330 For the Boas-Buck recurrence see A282629.
%F A321330 a(n) = denominator(beta(n)), with beta(n) = (-3)^{n+1}* B(n+1)/(n+1)!, where B(n) = A027641(n)/A027642(n) (Bernoulli).
%F A321330 The g.f. for {beta(n)}_{n>=0} is given in A321329.
%t A321330 a[n_] := Denominator[(-3)^(n+1)*BernoulliB[n+1]/(n+1)!]; Array[a, 30, 0] (* _Amiram Eldar_, Nov 15 2018 *)
%Y A321330 Cf. A027641/A027642, A282629, A321329.
%K A321330 nonn,frac,easy
%O A321330 0,1
%A A321330 _Wolfdieter Lang_, Nov 15 2018