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 A381593 #13 Mar 01 2025 08:37:29 %S A381593 1,2,11,88,869,9876,124473,1701630,24870695,384795184,6257294780, %T A381593 106377162620,1882982975521,34593496243070,657935674477431, %U A381593 12927331575084846,261951066040220637,5466177185459699916,117315664923801661485,2586804284853871362408 %N A381593 G.f. A(x) satisfies A(x) = 1/(1 - x * A(x) * A(x*A(x)))^2. %F A381593 See A381592. %F A381593 G.f.: B(x)^2, where B(x) is the g.f. of A381600. %o A381593 (PARI) a(n, k=2) = if(k==0, 0^n, k*sum(j=0, n, binomial(2*n+j+k, j)/(2*n+j+k)*a(n-j, 2*j))); %Y A381593 Column k=2 of A381592. %Y A381593 Cf. A088714, A381595. %Y A381593 Cf. A107096, A381572, A381600. %K A381593 nonn %O A381593 0,2 %A A381593 _Seiichi Manyama_, Mar 01 2025