OFFSET
0,3
COMMENTS
It appears that each nonconstant polynomial is irreducible if and only if its degree is p-1 for some prime p other than 3.
LINKS
Antti Karttunen, Table of n, a(n) for n = 0..2048
EXAMPLE
The 5 nonconstant irreducible divisors of the 5th polynomial appear in this factorization: -3 x (-2 + x) (-1 + x) (1 + x) (-1 + 2 x).
MATHEMATICA
PROG
(PARI) A326933(n) = { my(p=1/(1-x+x^2)); for(k=1, n, p = deriv(p)); #(factor(numerator(p)/n!)~); };
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Nov 01 2019
EXTENSIONS
Starting offset corrected from 1 to 0 by Antti Karttunen, Mar 02 2023
STATUS
approved