A113684 Expansion of x(1-x^2-x^3)/((1-x)(1-x-x^2))^2.

0, 1, 4, 11, 25, 52, 102, 193, 356, 645, 1153, 2040, 3580, 6241, 10820, 18671, 32089, 54956, 93826, 159745, 271300, 459721, 777409, 1312176, 2211000, 3719617, 6248452, 10482323, 17562841, 29391460, 49132638, 82048705, 136884260

Offset: 0

Author

Paul Barry, Nov 05 2005

Keywords

• easy
• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (4,-4,-2,4,0,-1)

Crossrefs

Cf. A045925, A006478, A023610.

Formula

a(n)=4a(n-1)-4a(n-2)-2a(n-3)+4a(n-4)-a(n-6); a(n)=sum{k=0..n, (n-k)*C(n-k, k+1)}; a(n)=n*(F(n+2)-1)-(1+((n-5)*F(n-1)+(3n-8)*F(n))/5).