A016211 Expansion of 1/((1-x)(1-3x)(1-6x)).

1, 10, 73, 478, 2989, 18298, 110881, 668566, 4021237, 24156946, 145030249, 870447214, 5223480445, 31343274154, 188066819377, 1128422439622, 6770599207813, 40623788957122, 243743314873465

Offset

0,2

Links

Table of n, a(n) for n=0..18.

Index entries for linear recurrences with constant coefficients, signature (10,-27,18).

Formula

a(n) = 9*a(n-1) - 18*a(n-2) + 1. - Vincenzo Librandi, Feb 10 2011

a(n) = 2*6^(n+1)/5 - 3^(n+1)/2 + 1/10. - R. J. Mathar, Feb 10 2011

a(n) = Sum_{k=0...n} 2^(k-1)*(3^(n+1) - 3^k). - J. M. Bergot, Feb 06 2018

Maple

a:=n->sum((6^(n-j+1)-3^(n-j+1))/3, j=0..n+1): seq(a(n), n=0..19); # Zerinvary Lajos, Jan 15 2007

Prog

(PARI) Vec(1/((1-x)*(1-3*x)*(1-6*x))+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012

Crossrefs

Sequence in context: A181402 A003366 A161743 * A055424 A243878 A200580

Adjacent sequences: A016208 A016209 A016210 * A016212 A016213 A016214

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved