A037504 Base-3 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,0.

1, 5, 15, 46, 140, 420, 1261, 3785, 11355, 34066, 102200, 306600, 919801, 2759405, 8278215, 24834646, 74503940, 223511820, 670535461, 2011606385, 6034819155, 18104457466, 54313372400, 162940117200, 488820351601

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base
• easy

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (3,0,1,-3).

Programs

Mathematica

Module[{nn=30,d},d=PadRight[{},nn,{1,2,0}];Table[FromDigits[Take[d,n],3],{n,nn}]] (* or *) LinearRecurrence[{3,0,1,-3},{1,5,15,46},30] (* Harvey P. Dale, Apr 25 2015 *)

Formula

G.f.: x*(1+2*x) / ( (x-1)*(3*x-1)*(1+x+x^2) ). - R. J. Mathar, Apr 27 2015