OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (2,1,0,-2).
FORMULA
a(n) = a(n-1) + 2*a(n-2) + 2*a(n-3) + 1. - Christian Krause, Jan 02 2023
MATHEMATICA
CoefficientList[Series[(1-x)^(-1)/(1-x-2x^2-2x^3), {x, 0, 40}], x] (* or *) LinearRecurrence[{2, 1, 0, -2}, {1, 2, 5, 12}, 40] (* Harvey P. Dale, Sep 14 2016 *)
PROG
(PARI) my(x='x+O('x^40)); Vec((1-x)^(-1)/(1-x-2*x^2-2*x^3)) \\ Christian Krause, Jan 02 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Nov 17 2002
STATUS
approved