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
KEYWORD
nonn,easy
AUTHOR
STATUS
approved