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A037603 Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,3,0. 4
1, 13, 130, 1301, 13013, 130130, 1301301, 13013013, 130130130, 1301301301, 13013013013, 130130130130, 1301301301301, 13013013013013, 130130130130130, 1301301301301301 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..16.

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

FORMULA

a(n)=10*a(n-1)+(1/9)*{13*(n mod 3)-2*[(n+1) mod 3]+[(n+2) mod 3]}, with a(0)=0 [From Paolo P. Lava, Jul 30 2009]

a(n)=10*a(n-1)+a(n-3)-10*a(n-4). G.f.: x*(1+3*x)/((x-1)*(10*x-1)*(1+x+x^2)). [From R. J. Mathar, Aug 03 2009]

MATHEMATICA

With[{mm=PadRight[{}, 18, {1, 3, 0}]}, Table[FromDigits[Take[mm, n]], {n, 18}]] (* Harvey P. Dale, Dec 13 2011 *)

CROSSREFS

Sequence in context: A255495 A121033 A006100 * A037708 A142740 A248919

Adjacent sequences:  A037600 A037601 A037602 * A037604 A037605 A037606

KEYWORD

nonn,base,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified March 19 11:10 EDT 2019. Contains 321329 sequences. (Running on oeis4.)