A134271 a(n) = a(n-2) + 2*a(n-3), n > 3; with a(0)=0, a(1)=1, a(2)=2, a(3)=0.

0, 1, 2, 0, 4, 4, 4, 12, 12, 20, 36, 44, 76, 116, 164, 268, 396, 596, 932, 1388, 2124, 3252, 4900, 7500, 11404, 17300, 26404, 40108, 61004, 92916, 141220, 214924, 327052, 497364, 756900, 1151468, 1751628, 2665268, 4054564, 6168524, 9385100

Offset

0,3

Comments

Recurrence in A052947.

Links

Table of n, a(n) for n=0..40.

Index entries for linear recurrences with constant coefficients, signature (0,1,2).

Formula

From R. J. Mathar, Feb 01 2008: (Start)

O.g.f.: 1/2 + (1/2)*(-2*x-5*x^2+1)/(-1+x^2+2*x^3).

a(n) = A052947(n-1) + 2*A052947(n-2) - A052947(n-3). (End)

Crossrefs

Cf. A078050.

Sequence in context: A049797 A116578 A078050 * A094403 A244340 A363062

Adjacent sequences: A134268 A134269 A134270 * A134272 A134273 A134274

Keyword

nonn,easy

Author

Paul Curtz, Jan 30 2008

Status

approved