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 A228426 #12 Feb 16 2025 08:33:20 %S A228426 0,1,33,282251,5170139875,36297634492764230063, %T A228426 43540989124396091246149,248033379485570104849994099153187946961, %U A228426 17204019459451797001978107903201762504044841332131 %N A228426 Numerator of Sum(i=1..n-1, 1/i^(2*n-1)). %C A228426 For prime p, p^3 divides a(p), see A130681. %H A228426 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/WolstenholmesTheorem.html">Wolstenholme's Theorem</a> %H A228426 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HarmonicNumber.html">Harmonic Number</a> %o A228426 (PARI) a(n)=numerator(sum(i=1,n-1,1/i^(2*n-1))) %Y A228426 Denominators are in A228427. %Y A228426 Cf. A001008/A002805. %K A228426 nonn,frac %O A228426 1,3 %A A228426 _Ralf Stephan_, Nov 10 2013