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%I #13 Aug 24 2023 07:49:54
%S 1,2,15,130,1263,13158,143704,1623766,18824931,222670678,2676674916,
%T 32604377358,401567277063,4992440157784,62569729324806,
%U 789679959184598,10027614784648750,128024712530277906,1642407060905790817,21161202394988206098
%N G.f. satisfies A(x) = ( 1 + x*A(x)^2 / (1 - x*A(x))^3 )^2.
%F If g.f. satisfies A(x) = ( 1 + x*A(x)^2 / (1 - x*A(x))^s )^t, then a(n) = Sum_{k=0..n} binomial(t*(n+k+1),k) * binomial(n+(s-1)*k-1,n-k)/(n+k+1).
%o (PARI) a(n, s=3, t=2) = sum(k=0, n, binomial(t*(n+k+1), k)*binomial(n+(s-1)*k-1, n-k)/(n+k+1));
%Y Cf. A365150, A365152.
%K nonn
%O 0,2
%A _Seiichi Manyama_, Aug 23 2023
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