A107885 Column 0 of triangle A107884.

1, 3, 6, 16, 63, 351, 2609, 24636, 284631, 3909926, 62459868, 1140206571, 23453446130, 537365482536, 13583603874930, 375783149051267, 11299149697288503, 367080116280553305, 12818485840320445236

Offset

0,2

Links

Table of n, a(n) for n=0..18.

Formula

G.f.: 1 = Sum_{k>=0} a(k)*x^k*(1-x)^(3 + k*(k-1)/2).

Example

1 = 1*(1-x)^3 + 3*x*(1-x)^3 + 6*x^2*(1-x)^4 +
16*x^3*(1-x)^6 + 63*x^4*(1-x)^9 + 351*x^5*(1-x)^13 +...

Prog

(PARI) {a(n)=polcoeff(1-sum(k=0, n-1, a(k)*x^k*(1-x+x*O(x^n))^(3+k*(k-1)/2)), n)}

Crossrefs

Cf. A107884, A107886, A107887, A107888.

Sequence in context: A340498 A288850 A185629 * A051271 A028405 A328276

Adjacent sequences: A107882 A107883 A107884 * A107886 A107887 A107888

Keyword

nonn

Author

Paul D. Hanna, Jun 04 2005

Status

approved