A107669 a(n) = A107668(n)/(n+1)^2.

1, 1, 5, 51, 809, 17575, 486460, 16384260, 650574249, 29762953831, 1541719486081, 89201504309927, 5702038255950404, 399105271607867940, 30359621863987241460, 2494052823831234355340, 220067051126228849480649

Offset: 0

Author

Paul D. Hanna, Jun 07 2005

Keywords

• nonn

Crossrefs

Cf. A107667, A107668, A107670.

Programs

PARI

{a(n)=local(A);if(n==0,n+1,A=(n+1)*x+x*O(x^n); for(k=0,n,A+=polcoeff(A,k)*x^k*(n+1-prod(i=0,k,1+(i-n-1)*x))); polcoeff(A,n)/(n+1)^2)}