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 A043304 #20 Feb 16 2021 13:51:21
%S A043304 504,264,24,28728,552,24,171864,24,24,151704,1128,264,86184,1416,24,
%T A043304 776664,18744,24,39816,1992,24,9796248,24,24,51912,2568,66792,504,24,
%U A043304 24,1098185256,34584,24,3292632,24,24,25951464,552,24,42143976,4008
%N A043304 Denominator of B(4n+2)/(8n+4) where B(m) are the Bernoulli numbers.
%D A043304 Bruce Berndt, Ramanujan's Notebooks Part II, Springer-Verlag; see Infinite series, p. 262.
%H A043304 Seiichi Manyama, <a href="/A043304/b043304.txt">Table of n, a(n) for n = 1..500</a>
%F A043304 B(4n+2)/(8n+4) = Sum_{k>=1} k^(4n+1)/(exp(2Pi*k)-1).
%t A043304 Denominator[Table[BernoulliB[4n+2]/(8n+4),{n,50}]] (* _Harvey P. Dale_, Sep 30 2012 *)
%o A043304 (PARI) a(n) = denominator(bernfrac(4*n+2)/(8*n+4)); \\ _Michel Marcus_, Feb 16 2021
%Y A043304 Cf. A043303.
%K A043304 easy,frac,nonn
%O A043304 1,1
%A A043304 _Benoit Cloitre_, Apr 04 2002