A133668 a(n) = a(n-1) - 36*a(n-2), a(0)=1, a(1)=6.

1, 6, -30, -246, 834, 9690, -20334, -369174, 362850, 13653114, 590514, -490921590, -512180094, 17160997146, 35599480530, -582196416726, -1863777715806, 19095293286330, 86191291055346, -601239267252534, -3704125745244990, 17940487875846234

Offset

0,2

Links

Matthew House, Table of n, a(n) for n = 0..1277

Index entries for linear recurrences with constant coefficients, signature (1,-36).

Formula

G.f.:(1+5*x)/(1-x+36*x^2).

a(n) = Sum_{k=0..n} A133607(n,k)*6^k. - Philippe Deléham, Dec 30 2007

Mathematica

CoefficientList[Series[(1+5x)/(1-x+36x^2), {x, 0, 40}], x] (* or *) LinearRecurrence[{1, -36}, {1, 6}, 40] (* Harvey P. Dale, Dec 28 2022 *)

Prog

(PARI) a(n)=([0, 1; -36, 1]^n*[1; 6])[1, 1] \\ Charles R Greathouse IV, Feb 15 2017

Crossrefs

Sequence in context: A009689 A228873 A366809 * A121772 A270845 A277073

Adjacent sequences: A133665 A133666 A133667 * A133669 A133670 A133671

Keyword

easy,sign

Author

Philippe Deléham, Dec 28 2007

Extensions

a(18) corrected by Matthew House, Feb 15 2017

Status

approved