A133680 a(n)=8*a(n-1)+72*a(n-2) for n>=3, a(0)=1, a(1)=8, a(2)=128 .

1, 8, 128, 1600, 22016, 291328, 3915776, 52301824, 700350464, 9368535040, 125373513728, 1677522632704, 22447074050048, 300358221955072, 4019055107244032, 53778232838717440, 719597830431309824

Offset

0,2

Links

Harvey P. Dale, Table of n, a(n) for n = 0..887

Index entries for linear recurrences with constant coefficients, signature (8,72).

Formula

G.f.: (1-8*x^2)/(1-8*x-72*x^2) . a(n) = Sum_{k, 0<=k<=n}A122950(n,k)*8^k .

a(n)=4*[4+2*sqrt(22)]^(n-1)+4*[4-2*sqrt(22)]^(n-1)+(12/11)*[4+2*sqrt(22)]^(n-1)*sqrt(22)-(12/11)*[4-2 *sqrt(22)]^(n-1)*sqrt(22)+(1/9)*[C(2*n,n) mod 2], with n>=0 [From Paolo P. Lava, Aug 28 2008]

Mathematica

LinearRecurrence[{8, 72}, {1, 8, 128}, 20] (* Harvey P. Dale, Sep 15 2015 *)

Crossrefs

Sequence in context: A036294 A298966 A299736 * A316811 A320367 A317561

Adjacent sequences: A133677 A133678 A133679 * A133681 A133682 A133683

Keyword

easy,nonn

Author

Philippe Deléham, Dec 31 2007

Status

approved