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 A111920 #11 Feb 16 2025 08:32:58
%S A111920 1,17,475,7627,960287,962287,330928441,5296012681,143167958387,
%T A111920 143231970419,190769776691689,190794429473689,419345761582878733,
%U A111920 419413977483774733,16780996063666453,268499592964601893
%N A111920 Numerator of x(n) = Sum_{k=1..n} ((odd part of k)/(k^4)).
%C A111920 Denominator of x(n) = A111921(n);
%C A111920 x(n) = a(n)/A111921(n) -> 14*zeta(3)/15.
%D A111920 G. Pólya and G. Szegő, Problems and Theorems in Analysis II (Springer 1924, reprinted 1972), Part Eight, Chap. 1, Sect. 6, Problem 50.
%H A111920 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/OddPart.html">Odd Part</a>
%H A111920 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/AperysConstant.html">Apery's constant</a>
%H A111920 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/RiemannZetaFunction.html">Riemann Zeta Function</a>
%e A111920 a(35) = 6357636538031086038114593391432155018318189,
%e A111920 A111921(35) = 5668063317569576031821812156438757376000000:
%e A111920 x(35) = a(35)/A111921(35) = 1.12165..., x(35)*15/14=1.20177....
%Y A111920 Cf. A000265, A002117, A111929, A111918, A111921, A111922.
%K A111920 nonn,frac
%O A111920 1,2
%A A111920 _Reinhard Zumkeller_, Aug 21 2005