A156641 a(n) = 13*(100^(n+1) - 1)/99.

13, 1313, 131313, 13131313, 1313131313, 131313131313, 13131313131313, 1313131313131313, 131313131313131313, 13131313131313131313, 1313131313131313131313, 131313131313131313131313

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Author

Vincenzo Librandi, Feb 15 2009

Keywords

• nonn
• easy

Examples

			For n=0, a(0)=13; n=1, a(1)=1313; n=2, a(2)=131313; n=3, a(3)=13131313.
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..100
• Index entries for linear recurrences with constant coefficients, signature (101,-100).

Crossrefs

Cf. A094028, A037582.

Programs

Magma

[13*(100^(n+1)-1)/99: n in [0..15]];

Maple

A156641:= n-> (13/99)*(10^(2*n+2) -1); seq(A156641(n), n=0..15); # G. C. Greubel, Feb 28 2021

Mathematica

Table[FromDigits[PadLeft[{1,3},2n,{1,3}]],{n,15}] (* Harvey P. Dale, Jul 23 2011 *)

PARI

a(n) = 100^(n+1)\99*13; \\ Kevin Ryde, Mar 05 2022

Sage

[(13/99)*(10^(2*n+2) -1) for n in (0..15)] # G. C. Greubel, Feb 28 2021

Formula

G.f.: 13*x / ( (1-100*x)*(1-x) ).

a(n) = 13*A094028(n-1).

E.g.f.: (13/99)*(-exp(x) + 100*exp(100*x)). - G. C. Greubel, Feb 28 2021

Extensions

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