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 A134827 #8 Sep 25 2024 09:25:49
%S A134827 1,2,8,18,78,206,872,2226,10820,26558,129248,335886,1630174,3990978,
%T A134827 21778450,48749804,274937594,650637382,3598954596,7610277626,
%U A134827 49741540498,93757794966,639655810986,1233712869392,8530089042832
%N A134827 Alternating row sums of triangle A134285, called s2(3)'.
%F A134827 a(n) = Sum_{m=1..n} A134285(n,m)*(-1)^(m-1).
%Y A134827 Cf. A134826 (row sums of triangle A134285).
%K A134827 nonn,easy
%O A134827 1,2
%A A134827 _Wolfdieter Lang_, Nov 13 2007