OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (16,-83,140).
FORMULA
a(n) = 16*4^n/3 -25*5^n/2 +49*7^n/6. - R. J. Mathar, Jun 29 2013
a(0)=1, a(1)=16, a(2)=173; for n>2, a(n) = 16*a(n-1) -83*a(n-2) +140*a(n-3). - Vincenzo Librandi, Jul 02 2013
a(n) = 12*a(n-1) -35*a(n-2) + 4^n. - Vincenzo Librandi, Jul 02 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - 4 x) (1 - 5 x) (1 - 7 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 02 2013 *)
LinearRecurrence[{16, -83, 140}, {1, 16, 173}, 30] (* Harvey P. Dale, Oct 18 2013 *)
PROG
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-4*x)*(1-5*x)*(1-7*x)))); /* or */ I:=[1, 16, 173]; [n le 3 select I[n] else 16*Self(n-1)-83*Self(n-2)+140*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 02 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved