OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (19,-110,200).
FORMULA
a(n) = 8*4^n/3 - 5*5^n/1 + 10*10^n/3. - R. J. Mathar, Jun 29 2013
From Vincenzo Librandi, Jul 02 2013: (Start)
a(n) = 19*a(n-1) - 110*a(n-2) + 200*a(n-3) for n > 2; a(0)=1, a(1)=19, a(2)=251.
a(n) = 15*a(n-1) - 50*a(n-2) + 4^n. (End)
MATHEMATICA
CoefficientList[Series[1 / ((1 - 4 x) (1 - 5 x) (1 - 10 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 02 2012 *)
PROG
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-4*x)*(1-5*x)*(1-10*x)))); /* or */ I:=[1, 19, 251]; [n le 3 select I[n] else 19*Self(n-1)-110*Self(n-2)+200*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 02 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved