OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (26,-217,624,-432).
FORMULA
a(n) = (5*12^(n+3) - 11*9^(n+3) + 11*4^(n+3) - 5)/1320. [Yahia Kahloune, Jul 05 2013]
a(0)=1, a(1)=26, a(2)=459, a(3)=6916; for n>3, a(n) = 26*a(n-1) -217*a(n-2) +624*a(n-3) -432*a(n-4). - Vincenzo Librandi, Jul 11 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - x) (1 - 4 x) (1 - 9 x) (1 - 12 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 11 2013 *)
PROG
(Magma) I:=[1, 26, 459, 6916]; [n le 4 select I[n] else 26*Self(n-1)-217*Self(n-2)+624*Self(n-3)-432*Self(n-4): n in [1..25]]; /* or */ m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-4*x)*(1-9*x)*(1-12*x)))); // Vincenzo Librandi, Jul 11 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved