A077899 Expansion of (1-x)^(-1)/(1+x-2*x^2+x^3).

1, 0, 3, -3, 10, -18, 42, -87, 190, -405, 873, -1872, 4024, -8640, 18561, -39864, 85627, -183915, 395034, -848490, 1822474, -3914487, 8407926, -18059373, 38789713, -83316384, 178955184, -384377664, 825604417, -1773314928, 3808901427, -8181135699, 17572253482, -37743426306

Offset: 0

Author

N. J. A. Sloane, Nov 17 2002

Keywords

• sign
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (0,3,-3,1).

Crossrefs

Cf. A002478.

Programs

PARI

Vec((1-x)^(-1)/(1+x-2*x^2+x^3)+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012

PARI

a(n) = (-1)^n*sum(k=0, n, binomial(2*k-1, n-k)); \\ Seiichi Manyama, Aug 13 2024

Formula

a(n) = (-1)^n * Sum_{k=0..n} binomial(2*k-1,n-k). - Seiichi Manyama, Aug 13 2024