A272659 Number of distinct characteristic polynomials of n X n matrices with elements {0, 1, 2}.

1, 3, 22, 513, 58335, 40422490

Offset

0,2

Links

Table of n, a(n) for n=0..5.

Robert M. Corless, Bohemian Eigenvalues, Talk Presented at Computational Discovery in Mathematics (ACMES 2), University of Western Ontario, May 12 2016. (Talk based on joint work with Steven E. Thornton, Sonia Gupta, Jonathan Brino-Tarasoff, Venkat Balasubramanian.)

Prog

(Python)
from itertools import product
from sympy import Matrix
def A272659(n): return len({tuple(Matrix(n, n, p).charpoly().as_list()) for p in product(range(3), repeat=n**2)}) if n else 1 # Chai Wah Wu, Sep 30 2023

Crossrefs

Six classes of matrices mentioned in Rob Corless's talk: A272658, A272659, A272660, A272661, A272662, A272663.

Sequence in context: A364844 A156512 A119770 * A233748 A153230 A195462

Adjacent sequences: A272656 A272657 A272658 * A272660 A272661 A272662

Keyword

nonn,more

Author

N. J. A. Sloane, May 15 2016

Extensions

a(4) from Chai Wah Wu, Dec 03 2018

a(5) from Steven E. Thornton, Mar 09 2019

a(0)=1 prepended by Alois P. Heinz, Sep 28 2023

Status

approved