A014927 a(1)=1, a(n) = n*12^(n-1) + a(n-1).

1, 25, 457, 7369, 111049, 1604041, 22505929, 309160393, 4178995657, 55776799177, 736867805641, 9652968253897, 125562274081225, 1623467149388233, 20882244117621193, 267394589311003081

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..900

Index entries for linear recurrences with constant coefficients, signature (25,-168,144).

Formula

a(1)=1, a(2)=25, a(n) = 24*a(n-1) - 144*a(n-2) + 1. - Vincenzo Librandi, Oct 23 2012

G.f.: x/((1 - x)*(1 - 12*x)^2). - Vincenzo Librandi, Oct 23 2012

Mathematica

CoefficientList[Series[1/((1 - x)(1 - 12*x)^2), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 23 2012 *)

Prog

(Magma) I:=[1, 25]; [n le 2 select I[n] else 24*Self(n-1) - 144*Self(n-2) + 1: n in [1..20]]; // Vincenzo Librandi, Oct 23 2012
(PARI) a(n) = (1+12^n*(11*n-1))/121; \\ Jinyuan Wang, Mar 11 2020

Crossrefs

Sequence in context: A131279 A056069 A089386 * A059946 A357147 A118445

Adjacent sequences: A014924 A014925 A014926 * A014928 A014929 A014930

Keyword

nonn,easy

Author

Olivier Gérard

Status

approved