A086611 Row sums of triangle of coefficients (A086610) where T(n,k) is the coefficient of x^n*y^k in f(x,y) that satisfies f(x,y) = (1-x-x^2)/(1-x)^2 + xy*f(x,y)^2.

1, 2, 4, 11, 36, 129, 486, 1892, 7546, 30675, 126642, 529600, 2238782, 9551583, 41075698, 177865921, 774875488, 3393896499, 14936139018, 66014016044, 292892796930, 1304062558529, 5824639004518, 26091657768331

Offset

0,2

Links

Table of n, a(n) for n=0..23.

Formula

G.f.: A(x) = (1-x-x^2)/(1-x)^2 + x*A(x)^2.

Example

a(3)=-1+1+6+5=11, a(4)=-2-2+6+20+14=36, a(5)=-3-6-4+30+70+42=129.

Crossrefs

Cf. A086610 (triangle), A086632.

Sequence in context: A219861 A193058 A179379 * A035098 A328425 A174107

Adjacent sequences: A086608 A086609 A086610 * A086612 A086613 A086614

Keyword

nonn

Author

Paul D. Hanna, Jul 24 2003

Status

approved