A165130 a(n) = (2^(n+4)-1)*(2^n-1).

0, 31, 189, 889, 3825, 15841, 64449, 259969, 1044225, 4185601, 16759809, 67074049, 268365825, 1073602561, 4294688769, 17179312129, 68718362625, 274875678721, 1099507171329, 4398037598209, 17592168218625, 70368708526081, 281474905407489

Offset

0,2

Links

Table of n, a(n) for n=0..22.

Index entries for linear recurrences with constant coefficients, signature (7, -14, 8).

Formula

a(n) = 7*a(n-1) -14*a(n-2)+8*a(n-3). G.f.: x*(31-28*x)/((1-x) * (2*x-1) * (4*x-1)). - R. J. Mathar, Sep 20 2009

a(n) = A000225(n+4) * A000225(n). - Michel Marcus, Jul 17 2013

Mathematica

LinearRecurrence[{7, -14, 8}, {0, 31, 189}, 30] (* Harvey P. Dale, Sep 25 2014 *)

Prog

(Quick Basic) DO: DIM x AS LONG: n = 0: x = ((2 ^ (n + 2)) - 1) * ((2 ^ (n - 2)) - 1): PRINT x: n = n + 1: LOOP
(PARI) a(n)=(2^(n+4)-1)*(2^n-1) \\ Charles R Greathouse IV, Jul 03 2016

Crossrefs

Sequence in context: A055788 A042876 A042878 * A229145 A261354 A023292

Adjacent sequences: A165127 A165128 A165129 * A165131 A165132 A165133

Keyword

nonn,easy

Author

Boris Hostnik (megpplus(AT)siol.net), Sep 04 2009

Extensions

Two initial fractional values removed by R. J. Mathar, Sep 20 2009

Status

approved