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,-77,134,-72).
FORMULA
a(0)=1, a(1)=16; for n>1, a(n) = 13*a(n-1) -36*a(n-2)+ 2^n - 1. - Vincenzo Librandi, Jul 06 2013
a(0)=1, a(1)=16, a(2)=179, a(3)=1766; for n>3, a(n) = 16*a(n-1) -77*a(n-2) +134*a(n-3) -72*a(n-4). - Vincenzo Librandi, Jul 06 2013
a(n) = (3*9^(n+3) - 28*4^(n+3) + 60*2^(n+3) - 35)/840. [Yahia Kahloune, Jul 07 2013]
MATHEMATICA
CoefficientList[Series[1 / ((1 - x) (1 - 2 x) (1 - 4 x) (1 - 9 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 06 2013 *)
PROG
(PARI) Vec(1/((1-x)*(1-2*x)*(1-4*x)*(1-9*x))+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012
(Magma) m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-x)*(1-2*x)*(1-4*x)*(1-9*x)))); /* or */ I:=[1, 16, 179, 1766]; [n le 4 select I[n] else 16*Self(n-1)-77*Self(n-2)+134*Self(n-3)-72*Self(n-4): n in [1..25]]; // Vincenzo Librandi, Jul 06 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved