A136326 a(n) = a(n-1) + 4a(n-2) - 4a(n-3).

1, 2, 4, 9, 17, 37, 69, 149, 277, 597, 1109, 2389, 4437, 9557, 17749, 38229, 70997, 152917, 283989, 611669, 1135957, 2446677, 4543829, 9786709, 18175317, 39146837, 72701269, 156587349, 290805077, 626349397, 1163220309, 2505397589, 4652881237, 10021590357

Offset: 0

Author

Paul Curtz, Mar 26 2008

Keywords

• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (1, 4, -4).

Programs

Mathematica

Join[{1},LinearRecurrence[{1,4,-4},{2,4,9},40]] (* Harvey P. Dale, Nov 27 2014 *)

Formula

G.f.: (1+x-2*x^2+x^3)/(1-x-4*x^2+4*x^3). - Harvey P. Dale, Nov 27 2014

Extensions

More terms from Harvey P. Dale, Nov 27 2014