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 A366953 #5 Sep 05 2025 00:22:29 %S A366953 0,0,2,18,156,1560,18600,262080,4284000,79833600,1671788160, %T A366953 38878963200,994367404800,27741377664000,838406080512000, %U A366953 27287153858764800,951529253875200000,35392677532692480000,1398727294865252352000,58529661706809925632000,2585234639710708457472000 %N A366953 Expansion of e.g.f. -log(1 - x^2/(1-x)^3). %C A366953 a(n) is the number of ways to choose two elements from each branch of labeled octopuses with n nodes. %C A366953 A328055(n) is the corresponding sequence if we choose one element only. %Y A366953 Cf. A029767, A328055. %K A366953 nonn,changed %O A366953 0,3 %A A366953 _Enrique Navarrete_, Oct 29 2023