A113664 Self-convolution 4th power of A113670, where a(n) = A113670(n+1)/(n+1).
1, 4, 38, 556, 10745, 254700, 7100444, 226687964, 8138624340, 324257974800, 14191562670382, 676772204063828, 34931592000218062, 1940427169943222088, 115440543670528170360, 7323969420842077029820, 493653199877341017573868
Offset: 0
Keywords
Links
- Vaclav Kotesovec, Table of n, a(n) for n = 0..360
Programs
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PARI
{a(n)=local(A=1+x*O(x^n));for(i=1,n, A=(1+x*deriv(x*A))^4);polcoeff(A,n,x)}
Formula
G.f. satisfies: A(x) = (1 + x*d/dx[x*A(x)] )^4.
a(n) ~ c * 4^n * n! * n^(3/4), where c = 0.71282302257258522141135342... - Vaclav Kotesovec, Oct 23 2020