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A033130 Base-3 digits are, in order, the first n terms of the periodic sequence with initial period 1,1,0. 1
1, 4, 12, 37, 112, 336, 1009, 3028, 9084, 27253, 81760, 245280, 735841, 2207524, 6622572, 19867717, 59603152, 178809456, 536428369, 1609285108, 4827855324, 14483565973, 43450697920, 130352093760, 391056281281, 1173168843844, 3519506531532, 10558519594597 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Colin Barker, Table of n, a(n) for n = 1..1000

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

FORMULA

a(n) = 3*a(n-1) + a(n-3) - 3*a(n-4).

G.f.: x*(1+x) / ((1-x)*(1-3*x)*(1+x+x^2)). - Colin Barker, Dec 24 2015

MATHEMATICA

Module[{nn=30, c}, c=PadRight[{}, nn, {1, 1, 0}]; Table[FromDigits[Take[c, n], 3], {n, nn}]] (* or *) LinearRecurrence[{3, 0, 1, -3}, {1, 4, 12, 37}, 30] (* Harvey P. Dale, Sep 01 2015 *)

PROG

(PARI) Vec(x*(1+x)/((1-x)*(1-3*x)*(1+x+x^2)) + O(x^30)) \\ Colin Barker, Dec 24 2015

CROSSREFS

Sequence in context: A183923 A279277 A101555 * A196918 A099098 A019481

Adjacent sequences:  A033127 A033128 A033129 * A033131 A033132 A033133

KEYWORD

nonn,base,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified May 28 21:37 EDT 2020. Contains 334690 sequences. (Running on oeis4.)