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 A381262 #9 Feb 18 2025 08:57:27
%S A381262 1,1,5,50,749,15132,385953,11907520,431376345,17954558928,
%T A381262 844397935517,44287052219104,2563077440429701,162259043437047104,
%U A381262 11154216390820950585,827464985582299977728,65889383717510410496689,5605511011776107945980160,507429545895353798767136181
%N A381262 Expansion of e.g.f. exp( -LambertW(-2 * sinh(x)) / 2 ).
%F A381262 E.g.f. A(x) satisfies A(x) = exp( sinh(x) * A(x)^2 ).
%F A381262 a(n) = Sum_{k=0..n} (2*k+1)^(k-1) * A136630(n,k).
%o A381262 (PARI) a136630(n, k) = 1/(2^k*k!)*sum(j=0, k, (-1)^(k-j)*(2*j-k)^n*binomial(k, j));
%o A381262 a(n) = sum(k=0, n, (2*k+1)^(k-1)*a136630(n, k));
%Y A381262 Cf. A136630, A219503.
%K A381262 nonn
%O A381262 0,3
%A A381262 _Seiichi Manyama_, Feb 18 2025