A385830 a(0) = 1; a(n) = Sum_{k=0..n-1} (1 + k^2) * a(k) * a(n-1-k).
1, 1, 3, 20, 241, 4623, 130300, 5100750, 265780029, 17827454651, 1498498011875, 154408489507578, 19151761451917580, 2815820822235814540, 484383420815495253624, 96401320782466194458886, 21981036279413999807199045, 5693391431445001330242504699, 1662538953499888924638316487305
Offset: 0
Keywords
Links
- Seiichi Manyama, Table of n, a(n) for n = 0..253
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, (1+j^2)*v[j+1]*v[i-j])); v;
Formula
G.f. A(x) satisfies A(x) = 1/( 1 - x*A(x) - x^2 * (d/dx A(x)) - x^3 * (d^2/dx^2 A(x)) ).