A360896 G.f. satisfies A(x) = 1 + x * A(x * (1 - x^2)).
1, 1, 1, 1, 0, -2, -5, -4, 9, 39, 46, -101, -516, -624, 2021, 9704, 8847, -58363, -230932, -65902, 2085381, 6301393, -5195375, -84748630, -174659303, 535875052, 3703162955, 3578704451, -39485091237, -163826467050, 88095454403, 2675998434838, 6571312338031
Offset: 0
Keywords
Links
- Seiichi Manyama, Table of n, a(n) for n = 0..952
Programs
-
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-1-2*j, j)*v[i-2*j])); v;
Formula
a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/3)} (-1)^k * binomial(n-1-2*k,k) * a(n-1-2*k).