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A037666 Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 3,1,0. 0
3, 31, 310, 3103, 31031, 310310, 3103103, 31031031, 310310310, 3103103103, 31031031031, 310310310310, 3103103103103, 31031031031031, 310310310310310, 3103103103103103 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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)*(7*(n mod 3) + 10*((n+1) mod 3) - 5*((n+2) mod 3)), with a(0)=0. - Paolo P. Lava, Jul 30 2009

G.f.: x*(3+x) / ( (x-1)*(10*x-1)*(1+x+x^2) ). - R. J. Mathar, Aug 04 2013

MATHEMATICA

Table[FromDigits[PadRight[{}, n, {3, 1, 0}]], {n, 30}] (* or *) LinearRecurrence[ {10, 0, 1, -10}, {3, 31, 310, 3103}, 30] (* Harvey P. Dale, Oct 11 2020 *)

PROG

(PARI) Vec(x*(3+x)/((x-1)*(10*x-1)*(1+x+x^2)) + O(x^25)) \\ Jinyuan Wang, Apr 14 2020

CROSSREFS

Sequence in context: A069589 A222090 A037778 * A065837 A100894 A065533

Adjacent sequences:  A037663 A037664 A037665 * A037667 A037668 A037669

KEYWORD

nonn,base,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified August 3 06:43 EDT 2021. Contains 346435 sequences. (Running on oeis4.)