OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (20,-117,198).
FORMULA
a(0)=1, a(1)=20, a(2)=283; for n>2, a(n) = 20*a(n-1) -117*a(n-2) +198*a(n-3). - Vincenzo Librandi, Jul 02 2013
a(n) = 17*a(n-1) -66*a(n-2) +3^n. - Vincenzo Librandi, Jul 02 2013
a(n) = (3*11^(n+2) - 8*6^(n+2) + 5*3^(n+2))/120. [Yahia Kahloune, Jul 06 2013]
MATHEMATICA
CoefficientList[Series[1 / ((1 - 3 x) (1 - 6 x) (1 - 11 x)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 02 2013 *)
LinearRecurrence[{20, -117, 198}, {1, 20, 283}, 30] (* Harvey P. Dale, Aug 31 2020 *)
PROG
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-3*x)*(1-6*x)*(1-11*x)))); /* or */ I:=[1, 20, 283]; [n le 3 select I[n] else 20*Self(n-1)-117*Self(n-2)+198*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 02 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved