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 A255006 #8 Feb 16 2025 08:33:24
%S A255006 1,1,8,8,128,176896,2048,3703808,1437433856,11443306496,40728264704,
%T A255006 123922856542208,5519125250048,56921405366730752,
%U A255006 231279728174802403328,258681888643685023744,325620148558310146048,113023230705723814256110993408
%N A255006 a(n) is the numerator of polygamma(2n+1, 1) / Pi^(2n+2).
%H A255006 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/PolygammaFunction.html">Polygamma Function</a>.
%H A255006 Wikipedia, <a href="http://en.wikipedia.org/wiki/Polygamma_function">Polygamma Function</a>.
%e A255006 Polygamma values {Pi^2/6, Pi^4/15, 8*Pi^6/63, 8*Pi^8/15, 128*Pi^10/33, ...} give numerators {1, 1, 8, 8, 128, ...} and denominators {6, 15, 63, 15, 33, ...}.
%t A255006 a[n_] := PolyGamma[2n+1, 1] / Pi^(2n+2) // Numerator; Table[a[n], {n, 0, 20}]
%Y A255006 Cf. A255007 (denominators).
%K A255006 nonn,frac,easy
%O A255006 0,3
%A A255006 _Jean-François Alcover_, Feb 12 2015