A360900 G.f. satisfies A(x) = 1 + x/(1 + x^3)^2 * A(x/(1 + x^3)).
1, 1, 1, 1, -1, -4, -8, -10, 2, 40, 115, 174, 22, -736, -2495, -4276, -920, 20593, 75011, 135814, 17524, -788871, -2909061, -5248648, 623274, 38581252, 138036877, 235567666, -134440249, -2284840691, -7698637124, -11745925435, 15869626983, 157479613343
Offset: 0
Keywords
Links
- Seiichi Manyama, Table of n, a(n) for n = 0..1000
Programs
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PARI
a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, (i-1)\3, (-1)^j*binomial(i-2*j, j)*v[i-3*j])); v;
Formula
a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/3)} (-1)^k * binomial(n-2*k,k) * a(n-1-3*k).