A385840 a(n) = 1 + Sum_{k=0..n-1} k^2 * a(k) * a(n-1-k).
1, 1, 2, 10, 101, 1733, 45303, 1680907, 84166419, 5475072843, 449157456364, 45377436182152, 5537042709272831, 802969519178558759, 136516626968319610486, 26895468447194766859402, 6078661245454015521843883, 1562271796018872884111521763, 453071380100390505646644605866
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)); for(i=0, n, v[i+1]=1+sum(j=0, i-1, j^2*v[j+1]*v[i-j])); v;
Formula
G.f. A(x) satisfies A(x) = 1/( (1 - x) * ( 1 - x^2 * (d/dx A(x)) - x^3 * (d^2/dx^2 A(x)) ) ).