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 A259927 #8 Feb 16 2025 08:33:26
%S A259927 4,2,7,5,9,7,7,3,6,4,4,9,1,8,5,0,9,4,1,9,9,1,6,7,1,4,9,0,1,6,0,6,7,2,
%T A259927 9,9,2,8,1,9,1,7,9,1,5,7,3,1,0,3,5,1,1,2,2,8,9,0,2,5,4,9,7,8,9,4,2,5,
%U A259927 1,6,7,3,2,2,9,3,9,6,2,0,4,0,8,3,4,1,9,1,2,0,5,7,9,9,8,2,3,1,0,1,2,9,6,5
%N A259927 Decimal expansion of sum_{n>=1} (PolyGamma(2, n+1)/n^3) (negated).
%H A259927 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/PolygammaFunction.html">Polygamma Function</a>.
%H A259927 Wikipedia, <a href="http://en.wikipedia.org/wiki/Polygamma_function">Polygamma Function</a>.
%F A259927 Equals zeta(6) - zeta(3)^2.
%e A259927 -0.427597736449185094199167149016067299281917915731035112289...
%t A259927 RealDigits[Zeta[6] - Zeta[3]^2, 10, 104] // First
%o A259927 (PARI) zeta(6) - zeta(3)^2 \\ _Michel Marcus_, Jul 09 2015
%Y A259927 Cf. A002117, A013664.
%K A259927 nonn,cons,easy
%O A259927 0,1
%A A259927 _Jean-François Alcover_, Jul 09 2015