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A037624 Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 2,0,3. 3
2, 20, 203, 2032, 20320, 203203, 2032032, 20320320, 203203203, 2032032032, 20320320320, 203203203203, 2032032032032, 20320320320320, 203203203203203, 2032032032032032, 20320320320320320, 203203203203203203, 2032032032032032032, 20320320320320320320 (list; graph; refs; listen; history; text; internal format)
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

a(n) = 10*a(n-1) + (1/9)*(-4*(n mod 3) + 11*((n+1) mod 3) + 8*((n+2) mod 3)) for n > 0. - Paolo P. Lava, Jul 30 2009

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

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Last modified August 5 00:15 EDT 2021. Contains 346456 sequences. (Running on oeis4.)