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

Author

Philippe Deléham, Dec 28 2007

Keywords

• easy
• sign

Links

• Matthew House, Table of n, a(n) for n = 0..1277
• Index entries for linear recurrences with constant coefficients, signature (1,-36).

Programs

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 *)

PARI

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

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

Extensions

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