OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (24,-185,450).
FORMULA
a(n) = 5*5^n/4 -81*9^n/4 +20*10^n. - R. J. Mathar, Jun 30 2013
a(0)=1, a(1)=24, a(2)=391; for n>2, a(n) = 24*a(n-1) -185*a(n-2) +450*a(n-3). - Vincenzo Librandi, Jul 03 2013
a(n) = 19*a(n-1) -90*a(n-2) +5^n. - Vincenzo Librandi, Jul 03 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - 5 x) (1 - 9 x) (1 - 10 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 03 2013 *)
LinearRecurrence[{24, -185, 450}, {1, 24, 391}, 20] (* Harvey P. Dale, Nov 27 2014 *)
PROG
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-5*x)*(1-9*x)*(1-10*x)))); /* or */ I:=[1, 24, 391]; [n le 3 select I[n] else 24*Self(n-1)-185*Self(n-2)+450*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 03 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved