A189801 a(n) = 6*a(n-1) + 9*a(n-2), with a(0)=0, a(1)=1.

0, 1, 6, 45, 324, 2349, 17010, 123201, 892296, 6462585, 46806174, 339000309, 2455257420, 17782547301, 128792600586, 932798529225, 6755924580624, 48930734246769, 354387726706230, 2566702968458301, 18589707351105876, 134638570822759965, 975138791096512674

Offset: 0

Author

Vladimir Joseph Stephan Orlovsky, May 24 2011

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (6,9).

Programs

Magma

I:=[0,1]; [n le 2 select I[n] else 6*Self(n-1) + 9*Self(n-2): n in [1..30]]; // G. C. Greubel, Jan 16 2018

Mathematica

LinearRecurrence[{6,9}, {0,1}, 50]

PARI

x='x+O('x^30); concat([0], Vec(x/(1 - 6*x - 9*x^2))) \\ G. C. Greubel, Jan 16 2018

Formula

G.f.: x/(1 - 6*x - 9*x^2). - R. J. Mathar, Nov 20 2011