A109268 Expansion of 1/((1-xc(x)-x^2c(x)^2)(1-x^2c(x))) with c(x) the g.f. of A000108.

1, 1, 4, 11, 36, 119, 407, 1418, 5018, 17971, 64989, 236915, 869518, 3209735, 11907644, 44368636, 165957615, 622880402, 2345005449, 8852862717, 33505203060, 127096279124, 483127286394, 1840030664115, 7020349647422

Offset: 0

Author

Paul Barry, Jun 24 2005

Keywords

• easy
• nonn

Comments

Diagonal sums of A109267.

Formula

G.f.: (2-x-x*sqrt(1-4x))(sqrt(1-4x)-x)/(2(1-4x-x^2)(1-x+x^3))