A166545 a(n) = 13*n - a(n-1), (with a(1)=13).

13, 13, 26, 26, 39, 39, 52, 52, 65, 65, 78, 78, 91, 91, 104, 104, 117, 117, 130, 130, 143, 143, 156, 156, 169, 169, 182, 182, 195, 195, 208, 208, 221, 221, 234, 234, 247, 247, 260, 260, 273, 273, 286, 286, 299, 299, 312, 312, 325, 325, 338, 338, 351, 351, 364, 364

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

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

Formula

G.f.: 13*x/((1-x)^2*(1+x)). - Vincenzo Librandi, Sep 13 2013

E.g.f.: (13/4)*((1 + 2*x)*exp(x) - exp(-x)). - G. C. Greubel, May 17 2016

Example

a(2) = 13*2 - 13 = 13;
a(3) = 13*3 - 13 = 26;
a(4) = 13*4 - 26 = 26.

Mathematica

Transpose[NestList[{First[#]+1, 13(First[#]+1)-Last[#]}&, {1, 13}, 70]] [[2]] (* or *) RecurrenceTable[{a[1]==13, a[n]==13n-a[n-1]}, a, {n, 70}] (* Harvey P. Dale, Jan 31 2012 *)
CoefficientList[Series[13 / ((1 - x)^2 (1 + x)), {x, 0, 70}], x] (* Vincenzo Librandi, Sep 13 2013 *)

Prog

(Magma) [(13/4)-(13/4)*(-1)^n+(13/2)*n: n in [1..70]]; // Vincenzo Librandi, Sep 13 2013

Crossrefs

Sequence in context: A303717 A040157 A003889 * A022347 A026907 A210475

Adjacent sequences: A166542 A166543 A166544 * A166546 A166547 A166548

Keyword

nonn,easy

Author

Vincenzo Librandi, Oct 22 2009

Extensions

Corrected by Harvey P. Dale, Jan 31 2012

Status

approved