A165638 a(n)=(6/7)*(2+5*(-6)^(n-1)).

1, 6, -24, 156, -924, 5556, -33324, 199956, -1199724, 7198356, -43190124, 259140756, -1554844524, 9329067156, -55974402924, 335846417556, -2015078505324, 12090471031956, -72542826191724, 435256957150356

Offset

0,2

Links

Table of n, a(n) for n=0..19.

Index entries for linear recurrences with constant coefficients, signature (-5,6).

Formula

a(n)=(-6)*a(n-1)+12 with a(0)=1. a(0)=1, a(1)=6, a(n)=6*a(n-2)-5*a(n-1). G.f.: (1+11x)/(1+5x-6x^2). a(n)= Sum_{k, 0<=k<=n} A112555(n,k)*5^(n-k).

Mathematica

LinearRecurrence[{-5, 6}, {1, 6}, 20] (* Harvey P. Dale, Jan 07 2016 *)

Crossrefs

Sequence in context: A265883 A330498 A165491 * A122829 A232688 A221980

Adjacent sequences: A165635 A165636 A165637 * A165639 A165640 A165641

Keyword

sign

Author

Philippe Deléham, Sep 23 2009

Status

approved