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 A281264 #23 Dec 12 2023 18:28:07
%S A281264 0,4,15,26,46,67,94,120,158,194,236,281,333,386,445,502,574,642,716,
%T A281264 792,875,960,1054,1143,1244,1345,1451,1560,1676,1793,1916,2036,2174,
%U A281264 2306,2444,2584,2731,2880,3034,3190,3356,3519,3690,3862,4041,4226,4413,4597,4796,4992
%N A281264 Base-2 logarithm of denominator of (Sum_{k=0..n^2-1} (-1)^k*sqrt(Pi)/(Gamma(1/2-k)*Gamma(1+k))) - n.
%t A281264 f[n_] := Log2[ Denominator[ Sum[ Binomial[2m, m]/4^m, {m, 0, n^2 -1}] -n]]; Array[f, 50]
%Y A281264 Cf. A280656, A007814.
%K A281264 nonn
%O A281264 1,2
%A A281264 _Ralf Steiner_, Apr 13 2017