A132804 A trisection of A024495.

0, 6, 42, 342, 2730, 21846, 174762, 1398102, 11184810, 89478486, 715827882, 5726623062, 45812984490, 366503875926, 2932031007402, 23456248059222, 187649984473770, 1501199875790166, 12009599006321322, 96076792050570582, 768614336404564650

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..300

Index entries for linear recurrences with constant coefficients, signature (7,8).

Formula

G.f.: 6*x/(1-7*x-8*x^2). a(n+1) = 7*a(n)+8*a(n-1) for n>=1, a(0)=0, a(1)=6. - Philippe Deléham, Nov 19 2007

a(n) = 2*A132805(n). - R. J. Mathar, Jun 07 2011

From Oboifeng Dira, Jun 05 2020: (Start)

a(n) = A078008(3n+1). Second trisection of A078008.

a(n) = 6*A015565(n).

a(n) = Sum_{k=0..n} binomial(3*n+1,3*k+2). (End)

Maple

A132804:=n->-(2/3)*(-1)^n+(2/3)*8^n: seq(A132804(n), n=0..30); # Wesley Ivan Hurt, Apr 14 2017

Mathematica

LinearRecurrence[{7, 8}, {0, 6}, 30] (* Harvey P. Dale, Mar 29 2018 *)

Prog

(Magma) [-(2/3)*(-1)^n+(2/3)*8^n: n in [0..25]]; // Vincenzo Librandi, Jun 08 2011
(PARI) a(n)=2*(8^n-(-1)^n)/3 \\ Charles R Greathouse IV, Jun 08 2011

Crossrefs

Cf. A132805, A078008, A015565.

Sequence in context: A361547 A123510 A265871 * A232473 A300693 A222062

Adjacent sequences: A132801 A132802 A132803 * A132805 A132806 A132807

Keyword

nonn,easy

Author

Paul Curtz, Nov 18 2007

Status

approved