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.

Showing 1-3 of 3 results.

A119002 Maximal determinant of real n X n symmetric (0,1) matrices.

Original entry on oeis.org

1, 1, 1, 2, 3, 5, 9, 18, 56, 144, 320
Offset: 0

Views

Author

Giovanni Resta, May 08 2006

Keywords

Comments

The determinant of this 8 X 8 matrix is a(8) = 56:
{0, 1, 1, 1, 0, 1, 0, 0},
{1, 0, 1, 1, 0, 1, 0, 0},
{1, 1, 0, 1, 0, 0, 1, 1},
{1, 1, 1, 0, 1, 0, 0, 1},
{0, 0, 0, 1, 1, 1, 0, 1},
{1, 1, 0, 0, 1, 1, 1, 0},
{0, 0, 1, 0, 0, 1, 1, 1},
{0, 0, 1, 1, 1, 0, 1, 0}
and the determinant of this 9 X 9 matrix is a(9) = 144:
{1, 1, 0, 1, 1, 0, 0, 1, 1},
{1, 1, 1, 1, 0, 1, 0, 0, 0},
{0, 1, 1, 1, 0, 0, 1, 1, 1},
{1, 1, 1, 0, 1, 0, 1, 0, 1},
{1, 0, 0, 1, 0, 1, 1, 0, 1},
{0, 1, 0, 0, 1, 1, 1, 1, 0},
{0, 0, 1, 1, 1, 1, 0, 0, 1},
{1, 0, 1, 0, 0, 1, 0, 1, 1},
{1, 0, 1, 1, 1, 0, 1, 1, 0}. - Jean-François Alcover, Nov 18 2017

Links

Crossrefs

Cf. A003432, A119003, A119004, A118998.

Formula

a(n) <= A003432(n).

Extensions

a(8) and a(9) from Jean-François Alcover, Nov 18 2017
a(0)=1 prepended by Alois P. Heinz, Nov 18 2017
a(10) from Max Alekseyev, Jun 17 2025

A119006 Number of n X n real symmetric (0,1)-matrices having minimal determinant (=A118998(n)).

Original entry on oeis.org

1, 3, 3, 8, 60, 1620, 840, 23520, 756000, 30996000
Offset: 1

Views

Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Cf. A118998, A119002, A119004, A119007.

Extensions

a(8)-a(10) from Max Alekseyev, Jun 17 2025

A119005 Number of n X n real symmetric (+1,-1)-matrices having maximal determinant (=A119003(n)).

Original entry on oeis.org

1, 4, 16, 48, 416, 3840, 161280, 215040, 15482880, 774144000
Offset: 1

Views

Author

Giovanni Resta, May 08 2006

Keywords

Links

Crossrefs

Cf. A119004, A119003, A119004, A119007.

Extensions

a(8)-a(10) from Max Alekseyev, Jun 17 2025
Showing 1-3 of 3 results.

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