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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
OFFSET
1,1
FORMULA
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
KEYWORD
nonn,base,easy
STATUS
approved