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 A163929 #12 May 07 2020 06:15:52
%S A163929 1,1,16,1296,20736,12960000,4320000,10372320000,165957120000,
%T A163929 40327580160000,40327580160000,590436101122560000,590436101122560000,
%U A163929 16863445484161436160000,2409063640594490880000,2409063640594490880000
%N A163929 Denominators of the higher order exponential integral constants alpha(2,n).
%C A163929 See A163927 for information about the constants alpha(k,n).
%F A163929 alpha(k,n) = (1/k)*Sum_{i=0..k-1} Sum_{p=0..n-1} p^(-2*(k-i))*alpha(i, n) with alpha(0,n) = 1. For this sequence, k = 2 and n >= 1.
%e A163929 alpha(k=2, n=1) = 0, alpha(k=2, 2) = 1, alpha(k=2, 3) = 21/16, and alpha(k=2, 4) = 1897/1296.
%Y A163929 Cf. A163928 (numerators).
%K A163929 nonn,frac
%O A163929 1,3
%A A163929 _Johannes W. Meijer_ & _Nico Baken_, Aug 13 2009, Aug 17 2009