OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (25,-192,432)
FORMULA
a(n) = 2*4^n/5 -3^(2n+3)/5 +12^n*6. - R. J. Mathar, Nov 11 2012
a(0)=1, a(1)=25, a(2)=433; for n>2, a(n) = 25*a(n-1) -192*a(n-2) +432*a(n-3). - Vincenzo Librandi, Jul 03 2013
a(n) = 21*a(n-1) -108*a(n-2) +4^n. - Vincenzo Librandi, Jul 03 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - 4 x) (1 - 9 x) (1 - 12 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 03 2013 *)
LinearRecurrence[{25, -192, 432}, {1, 25, 433}, 30] (* Harvey P. Dale, Oct 30 2013 *)
PROG
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-4*x)*(1-9*x)*(1-12*x)))); /* or */ I:=[1, 25, 433]; [n le 3 select I[n] else 25*Self(n-1)-192*Self(n-2)+432*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 03 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved