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 A156563 #8 Aug 03 2021 04:47:51
%S A156563 2,2,6,5,8,8,10,12,14,14,17,18,20,20,24,24,27,26,30,28,34,31,36,34,40,
%T A156563 38,42,41,44,45,47,47,50,49,54,53,57,55,60,59,62,62,64,66,67,68,70,70,
%U A156563 74,74,76,77,80,80,82,83,84,87,88,90,90,94,94,96,97,100,101
%N A156563 a(n) = (-1)^n*Sum_{k=1..n} A078649(k)*(-1)^k.
%H A156563 Jinyuan Wang, <a href="/A156563/b156563.txt">Table of n, a(n) for n = 1..1000</a>
%Y A156563 Cf. A078649, A156562.
%K A156563 nonn
%O A156563 1,1
%A A156563 _Benoit Cloitre_, Feb 10 2009