A077890 Expansion of (1-x)^(-1)/(1+x^2+2*x^3).

1, 1, 0, -2, -1, 3, 6, 0, -11, -11, 12, 34, 11, -57, -78, 36, 193, 121, -264, -506, 23, 1035, 990, -1080, -3059, -899, 5220, 7018, -3421, -17457, -10614, 24300, 45529, -3071, -94128, -87986, 100271, 276243, 75702, -476784, -628187, 325381, 1581756, 930994, -2232517, -4094505, 370530

Offset

0,4

Links

Table of n, a(n) for n=0..46.

Index entries for linear recurrences with constant coefficients, signature (1,-1,-1,2).

Formula

a(n) = a(n-1) - a(n-2) - a(n-3) + 2*a(n-4). - Wesley Ivan Hurt, Jun 23 2026

Mathematica

CoefficientList[Series[(1-x)^(-1)/(1+x^2+2*x^3), {x, 0, 50}], x] (* Harvey P. Dale, Apr 07 2018 *)
(* Alternative: *)
LinearRecurrence[{1, -1, -1, 2}, {1, 1, 0, -2}, 50] (* Harvey P. Dale, Apr 07 2018 *)

Prog

(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; 2, -1, -1, 1]^n*[1; 1; 0; -2])[1, 1] \\ Charles R Greathouse IV, Jun 02 2026

Crossrefs

Sequence in context: A397525 A143581 A096871 * A077877 A144867 A081520

Adjacent sequences: A077887 A077888 A077889 * A077891 A077892 A077893

Keyword

sign,easy

Author

N. J. A. Sloane, Nov 17 2002

Status

approved