%I #16 Mar 16 2023 02:48:57
%S 1,1,7,97,2049,58541,2114143,92419965,4746108769,280105517881,
%T 18683156508471,1389960074426969,114119472522112225,
%U 10249863809271551973,999746622121255094479,105236583967331849218741,11891012005206169120252737,1435560112909007680593616625
%N E.g.f. satisfies A(x) = exp( 1/(1 - x * A(x)^2) - 1 ).
%H Winston de Greef, <a href="/A361093/b361093.txt">Table of n, a(n) for n = 0..334</a>
%F a(n) = n! * Sum_{k=0..n} (2*n+1)^(k-1) * binomial(n-1,n-k)/k!.
%F a(n) ~ n^(n-1) / (2 * 3^(1/4) * (2 - sqrt(3))^n * exp((2 - sqrt(3))*n - (sqrt(3) - 1)/2)). - _Vaclav Kotesovec_, Mar 02 2023
%t Table[n! * Sum[(2*n+1)^(k-1) * Binomial[n-1,n-k]/k!, {k,0,n}], {n,0,20}] (* _Vaclav Kotesovec_, Mar 02 2023 *)
%o (PARI) a(n) = n!*sum(k=0, n, (2*n+1)^(k-1)*binomial(n-1, n-k)/k!);
%Y Cf. A052873, A361094, A361095, A361096, A361097.
%Y Cf. A212722, A361065.
%K nonn
%O 0,3
%A _Seiichi Manyama_, Mar 01 2023