A364736 G.f. satisfies A(x) = 1 + x*A(x) / (1 + x*A(x)^3).
1, 1, 0, -3, -3, 17, 45, -90, -546, 130, 5832, 7074, -53625, -159214, 374517, 2419131, -728364, -30011530, -37519884, 307731042, 940757526, -2343385995, -15421126275, 5164279686, 203045257272, 255851517115, -2186669342070, -6760669947375, 17391580425180
Offset: 0
Keywords
Programs
-
PARI
a(n) = if(n==0, 1, sum(k=0, n-1, (-1)^k*binomial(n, k)*binomial(n+2*k, n-1-k))/n);
Formula
a(n) = (1/n) * Sum_{k=0..n-1} (-1)^k * binomial(n,k) * binomial(n+2*k,n-1-k) for n > 0.