A090354 Self-convolution equals the binomial transform of A090353: A^2 = BINOMIAL(A090353).
1, 1, 3, 19, 190, 2574, 43922, 903986, 21784659, 601478195, 18715354049, 647834803569, 24688869993252, 1027073272425876, 46309250293477020, 2249435671825385244, 117101538463333719891, 6503918951175618656403
Offset: 0
Keywords
Links
- Vaclav Kotesovec, Table of n, a(n) for n = 0..370
Programs
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PARI
{a(n)=local(A); if(n<1,0,A=1+x+x*O(x^n); for(k=1,n,B=subst(A^3,x, x/(1-x))/(1-x)+x*O(x^n); A=A-A^4+B);B=subst(A,x, x/(1-x))/(1-x)+x*O(x^n); polcoeff(B^(1/2),n,x))}
Formula
a(n) ~ (n-1)! / (18 * log(4/3)^(n+1)). - Vaclav Kotesovec, May 28 2025
Comments