This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A365926 #27 May 20 2025 09:03:27
%S A365926 1,1,6,513,2875405
%N A365926 Number of distinct characteristic polynomials for n X n matrices with entries in {0, 1, ..., n-1}.
%H A365926 Robert P. P. McKone, <a href="/A365926/a365926.txt">The distinct characteristic polynomials for a(2)-a(3)</a>.
%t A365926 a[n_] := Module[{polynomials = {}, polynomial}, Monitor[Do[polynomial = CharacteristicPolynomial[ArrayReshape[IntegerDigits[i, n, n^2], {n, n}], x]; If[Not[MemberQ[polynomials, polynomial]], AppendTo[polynomials, polynomial]];, {i, 0, n^(n^2) - 1}], {n, {i, n^(n^2) - 1}, ProgressIndicator[i, {0, n^(n^2) - 1}]}]; Length[polynomials]]; Table[a[n], {n, 1, 3}]
%o A365926 (Python)
%o A365926 from itertools import product
%o A365926 from sympy import Matrix
%o A365926 def A365926(n): return len({tuple(Matrix(n,n,p).charpoly().as_list()) for p in product(range(n),repeat=n**2)}) if n else 1 # _Chai Wah Wu_, Sep 30 2023
%Y A365926 Cf. A272661, A272659.
%Y A365926 Cf. A272658, A272660, A272662, A272663.
%K A365926 nonn,hard,more,bref
%O A365926 0,3
%A A365926 _Robert P. P. McKone_, Sep 23 2023
%E A365926 a(4) from _Robin Visser_, May 04 2025