A136326 - OEIS

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

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OFFSET

0,2

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).

FORMULA

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

MATHEMATICA

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

CROSSREFS

Sequence in context: A291728 A268649 A316983 * A362033 A059973 A030035