OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..200
Max Alekseyev, PARI scripts for various problems
Arnaud Bodin, Number of irreducible polynomials in several variables over finite fields, arXiv:0706.0157 [math.AC], 2007.
FORMULA
a(n) = A020514(n) - 1, or a(n) = 2^n + 4^n + 8^n + 16^n. - Chris Boyd, Apr 26 2014
G.f.: x*(30-560*x+2880*x^2-4096*x^3)/((1-2*x)(1-4*x)(1-8*x)(1-16*x)). - Vincenzo Librandi, Apr 28 2014
MATHEMATICA
CoefficientList[Series[(30 - 560 x + 2880 x^2 - 4096 x^3)/((1 - 2 x) (1 - 4 x) (1 - 8 x) (1 - 16 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Apr 28 2014 *)
PROG
(PARI) a(n) = numirrpol(2^n, 4, 1)[1]; \\ using numirrpol script from Max Alekseyev, Michel Marcus, Apr 28 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Max Alekseyev, Jan 16 2006
STATUS
approved