A033139 Base 3 digits are, in order, the first n terms of the periodic sequence with initial period 1,0,0.

1, 3, 9, 28, 84, 252, 757, 2271, 6813, 20440, 61320, 183960, 551881, 1655643, 4966929, 14900788, 44702364, 134107092, 402321277, 1206963831, 3620891493, 10862674480, 32588023440, 97764070320, 293292210961, 879876632883

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (3,0,1,-3).

Formula

G.f.: 1/((1-3*x)*(1-x^3)). - Paul Barry, May 02 2003

a(n) = 3^(n+3)/26 -1/6 +(5*A049347(n)+7*A049347(n-1))/39. - R. J. Mathar, Mar 19 2011

Mathematica

CoefficientList[Series[1/((1-3x)(1-x^3)), {x, 0, 1001}], x] (* Vincenzo Librandi, Apr 04 2012 *)

Prog

(PARI) x='x+O('x^50); Vec(1/((1-3*x)*(1-x^3))) \\ G. C. Greubel, Sep 26 2017

Crossrefs

Cf. A000975.

Sequence in context: A027099 A292328 A027090 * A372870 A291731 A291257

Adjacent sequences: A033136 A033137 A033138 * A033140 A033141 A033142

Keyword

nonn,base,easy

Author

Clark Kimberling

Status

approved