cp's OEIS Frontend

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.

A091470 Number of n X n matrices with entries {-1,0,1} that are diagonalizable over the complex numbers.

Original entry on oeis.org

3, 65, 15627, 36625153
Offset: 1

Views

Author

Eric W. Weisstein, Jan 12 2004

Keywords

Comments

See A091472 for definition of diagonalizable and for Mathematica definitions.

Crossrefs

Programs

  • Mathematica
    Table[Count[Matrices[n, {-1, 0, 1}], _?DiagonalizableQ], {n, 4}]
  • Sage
    import itertools
    def a(n):
        ans, W = 0, itertools.product([-1,0,1], repeat=n*n)
        for w in W:
            if Matrix(QQbar, n, n, w).is_diagonalizable(): ans += 1
        return ans  # Robin Visser, Sep 24 2023

Extensions

a(4) from Robin Visser, Sep 24 2023