OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (23,-170,400).
FORMULA
a(n) = 5^(n+1)/3 -4*8^(n+1)/3+10^(n+1). - R. J. Mathar, Mar 15 2011
a(0)=1, a(1)=23, a(2)=359; for n>2, a(n) = 23*a(n-1) -170*a(n-2) +400*a(n-3). - Vincenzo Librandi, Jul 03 2013
a(n) = 18*a(n-1) -80*a(n-2) +5^n. - Vincenzo Librandi, Jul 03 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - 5 x) (1 - 8 x) (1 - 10 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 03 2013 *)
PROG
(PARI) a(n) = 5^(n+1)/3-32*8^n/3+10^(n+1) \\ Charles R Greathouse IV, Sep 26 2012
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-5*x)*(1-8*x)*(1-10*x)))); // Vincenzo Librandi, Jul 03 2013
(Magma) I:=[1, 23, 359]; [n le 3 select I[n] else 23*Self(n-1)-170*Self(n-2)+400*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 03 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved