A121720 a(n) = 4*a(n-2) - 2*a(n-4).

0, 1, 1, 3, 4, 10, 14, 34, 48, 116, 164, 396, 560, 1352, 1912, 4616, 6528, 15760, 22288, 53808, 76096, 183712, 259808, 627232, 887040, 2141504, 3028544, 7311552, 10340096, 24963200, 35303296, 85229696, 120532992, 290992384, 411525376, 993510144, 1405035520

Offset

1,4

Links

Table of n, a(n) for n=1..37.

Index entries for linear recurrences with constant coefficients, signature (0, 4, 0, -2).

Formula

a(n) = A007068(n-2), n>2.

G.f.: -x^2*(-1-x+x^2)/(1-4*x^2+2*x^4). [Oct 14 2009]

Mathematica

LinearRecurrence[{0, 4, 0, -2}, {0, 1, 1, 3}, 30] (* Harvey P. Dale, May 21 2014 *)

Crossrefs

Cf A002530, A048788.

Sequence in context: A134512 A106523 A007068 * A056515 A056516 A056517

Adjacent sequences: A121717 A121718 A121719 * A121721 A121722 A121723

Keyword

nonn,easy,less

Author

Roger L. Bagula and Gary W. Adamson, Sep 07 2006

Extensions

Definition replaced by recurrence - The Assoc. Editors of the OEIS, Oct 14 2009

More terms from Harvey P. Dale, May 21 2014

Status

approved