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%I #22 Dec 14 2023 05:34:36
%S 1,13,130,1301,13013,130130,1301301,13013013,130130130,1301301301,
%T 13013013013,130130130130,1301301301301,13013013013013,
%U 130130130130130,1301301301301301
%N Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,3,0.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (10,0,1,-10).
%F 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)). - _R. J. Mathar_, Aug 03 2009
%t With[{mm=PadRight[{},18,{1,3,0}]},Table[FromDigits[Take[mm,n]],{n,18}]] (* _Harvey P. Dale_, Dec 13 2011 *)
%o (PARI) Vec(x*(1+3*x)/((x-1)*(10*x-1)*(1+x+x^2)) + O(x^25)) \\ _Jinyuan Wang_, Apr 14 2020
%K nonn,base,easy
%O 1,2
%A _Clark Kimberling_
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