A367029 G.f. satisfies A(x) = 1 + x*A(x) - x^2*A(x)^4.
1, 1, 0, -4, -10, 2, 89, 249, -91, -2811, -8071, 4201, 103617, 297201, -200421, -4167581, -11798389, 9803475, 177275251, 492087227, -488311177, -7839760737, -21249466773, 24651743523, 356735365223, 941396264159, -1257287146286, -16589782316762
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n\2, (-1)^k*binomial(n+2*k, k)*binomial(n+k, n-2*k)/(3*k+1));
Formula
a(n) = Sum_{k=0..floor(n/2)} (-1)^k * binomial(n+2*k,k) * binomial(n+k,n-2*k) / (3*k+1).