A364629 G.f. satisfies A(x) = (1+x*A(x)^3)/(1-x)^2.
1, 3, 14, 94, 735, 6239, 55888, 520028, 4977321, 48689260, 484623552, 4892304686, 49971163021, 515496741918, 5363023614620, 56204877993184, 592811175777029, 6287909183751105, 67029933733468729, 717749621979800340, 7716543390041275964
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n, binomial(n+5*k+1, 6*k+1)*binomial(3*k, k)/(2*k+1));
Formula
a(n) = Sum_{k=0..n} binomial(n+5*k+1,6*k+1) * binomial(3*k,k) / (2*k+1).