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A037581 Base 9 digits are, in order, the first n terms of the periodic sequence with initial period 1,3. 1
1, 12, 109, 984, 8857, 79716, 717445, 6457008, 58113073, 523017660, 4707158941, 42364430472, 381279874249, 3431518868244, 30883669814197, 277953028327776, 2501577254949985, 22514195294549868, 202627757650948813, 1823649818858539320, 16412848369726853881 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

Index entries for linear recurrences with constant coefficients, signature (9,1,-9).

FORMULA

a(n) = (3^(1+2*n)+2*(-1)^n-5)/20. a(n) = 9*a(n-1)+a(n-2)-9*a(n-3). G.f.: x*(3*x+1) / ((x-1)*(x+1)*(9*x-1)). [Colin Barker, Dec 27 2012]

MATHEMATICA

CoefficientList[Series[(3 x + 1)/((x - 1) (x + 1) (9 x - 1)), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 22 2013 *)

Module[{nn=30, d}, d=PadRight[{}, nn, {1, 3}]; Table[FromDigits[Take[d, n], 9], {n, nn}]] (* Harvey P. Dale, Jul 22 2015 *)

PROG

(MAGMA) [(3^(1+2*n)+2*(-1)^n-5)/20: n in [1..30]]; // Vincenzo Librandi, Oct 22 2013

CROSSREFS

Sequence in context: A016161 A081200 A016214 * A177071 A081183 A069294

Adjacent sequences:  A037578 A037579 A037580 * A037582 A037583 A037584

KEYWORD

nonn,base,easy

AUTHOR

Clark Kimberling

EXTENSIONS

More terms from Colin Barker, Dec 27 2012

STATUS

approved

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Last modified September 25 06:05 EDT 2020. Contains 337335 sequences. (Running on oeis4.)