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 A154381 #4 Sep 03 2022 22:39:47 %S A154381 1,2,6,20,72,276,1120,4804,21796,104784,534788,2901580,16742440, %T A154381 102654356,667519492,4590552960,33278208004,253436345340, %U A154381 2020974497112,16823488830836,145798111066964,1312272490908464 %N A154381 Row sums of Bell related number triangle A154380. %C A154381 a(n) = 2*A129247(n), n>0. Hankel transform is 2^n*A000178(n). %F A154381 G.f.: 1/(1-2x/(1-x/(1-x/(1-2x/(1-x/(1-3x/(1-x/(1-4x/(1-... (continued fraction). %Y A154381 Cf. A000110, A000178, A129247, A154380. %K A154381 easy,nonn %O A154381 0,2 %A A154381 _Paul Barry_, Jan 08 2009