A037624 Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 2,0,3.

2, 20, 203, 2032, 20320, 203203, 2032032, 20320320, 203203203, 2032032032, 20320320320, 203203203203, 2032032032032, 20320320320320, 203203203203203, 2032032032032032, 20320320320320320, 203203203203203203, 2032032032032032032, 20320320320320320320

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Index entries for linear recurrences with constant coefficients, signature (10,0,1,-10).

Formula

G.f.: x*(2+3*x^2) / ( (x-1)*(10*x-1)*(1+x+x^2) ). - R. J. Mathar, Nov 21 2011

Mathematica

CoefficientList[Series[(2 + 3 x^2) / ((x - 1) (10 x - 1) (1 + x + x^2)), {x, 0, 20}], x] (* Vincenzo Librandi, Feb 16 2018 *)

Prog

(Magma) I:=[2, 20, 203, 2032]; [n le 4 select I[n] else 10*Self(n-1)+Self(n-3)-10*Self(n-4): n in [1..30]]; // Vincenzo Librandi, Feb 16 2018

Crossrefs

Sequence in context: A037722 A109107 A037729 * A077327 A173499 A067636

Adjacent sequences: A037621 A037622 A037623 * A037625 A037626 A037627

Keyword

nonn,base

Author

Clark Kimberling

Status

approved