A134654 a(n) = 2a(n-2)+4a(n-3), n > 3.

0, 0, 2, 1, 4, 10, 12, 36, 64, 120, 272, 496, 1024, 2080, 4032, 8256, 16384, 32640, 65792, 130816, 262144, 524800, 1047552, 2098176, 4194304, 8386560, 16781312, 33550336, 67108864, 134225920, 268419072, 536887296, 1073741824, 2147450880

Offset

0,3

Links

Table of n, a(n) for n=0..33.

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

Formula

O.g.f.: -x^2(2+x)/[(2x-1)(2x^2+2x+1)] . a(n) = [2^(n-1)-A108520(n-1)]/2 if n>0. - R. J. Mathar, Jan 29 2008

Mathematica

LinearRecurrence[{0, 2, 4}, {0, 0, 2, 1}, 40] (* or *) CoefficientList[ Series[ -((x^2 (2+x))/(-1+2 x^2+4 x^3)), {x, 0, 40}], x] (* Harvey P. Dale, Jul 02 2021 *)

Crossrefs

Cf. A038521.

Sequence in context: A205855 A329709 A038521 * A198262 A085421 A001071

Adjacent sequences: A134651 A134652 A134653 * A134655 A134656 A134657

Keyword

nonn,easy

Author

Paul Curtz, Jan 25 2008

Extensions

More terms from R. J. Mathar, Jan 29 2008

Status

approved