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 A036654 #15 Jan 29 2022 00:42:31 %S A036654 1,1,1,2,2,2,4,6,8,8,10,18,34,52,52,24,58,136,288,472,472,66,186,538, %T A036654 1424,3224,5504,5504,180,614,2080,6648,18888,44712,78416,78416,522, %U A036654 2034,7970,29700,101340,302096,738448,1320064,1320064 %N A036654 Triangle of series-parallel numbers. %D A036654 J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 142. %e A036654 Triangle begins %e A036654 1; %e A036654 1, 1; %e A036654 2, 2, 2; %e A036654 4, 6, 8, 8; %e A036654 ... %K A036654 nonn,easy,tabl,nice %O A036654 0,4 %A A036654 _N. J. A. Sloane_ %E A036654 a(35) corrected by _Sean A. Irvine_, Nov 15 2020