OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (23,-181,537,-378).
FORMULA
a(n) = (5*9^(n+3)-20*7^(n+3)+16*6^(n+3)-1)/240. [Yahia Kahloune, May 25 2013]
a(0)=1, a(1)=23, a(2)=348, a(3)=4378; for n>3, a(n) = 23*a(n-1) -181*a(n-2) +537*a(n-3) -378*a(n-4). - Vincenzo Librandi, Jul 12 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - x) (1 - 6 x) (1 - 7 x) (1 - 9 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 12 2013 *)
PROG
(Magma) I:=[1, 23, 348, 4378]; [n le 4 select I[n] else 23*Self(n-1)-181*Self(n-2)+537*Self(n-3)-378*Self(n-4): n in [1..25]]; /* or */ m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-6*x)*(1-7*x)*(1-9*x)))); // Vincenzo Librandi, Jul 12 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved