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 1-5 of 5 results.

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

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

A118996 Number of real n X n symmetric (0,1) matrices with negative determinant.

Original entry on oeis.org

0, 3, 27, 190, 4410, 753592, 127793708, 21893984392, 9100020369720, 16451259308386616
Offset: 1

Views

Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Cf. A086899, A086900, A086906, A118997, A118998, A118999, A119006.

Formula

a(n) = A086899(n) - A086900(n) = 2^(n*(n+1)/2) - A086906(n) - A086900(n). - Max Alekseyev, Jun 12 2025

Extensions

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

A119000 Minimal determinant of real n X n symmetric (+1,-1) matrices.

Original entry on oeis.org

-1, -2, -4, -16, -48, -160, -576, -2304, -14336, -73728
Offset: 1

Views

Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Cf. A118998, A119001, A119003, A119007.

Extensions

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

A119008 Number of n X n real symmetric (0,1)-matrices with determinant = 1.

Original entry on oeis.org

1, 1, 4, 268, 9456, 301306, 24846368, 8946957244, 4175660906560, 2421067614753916
Offset: 1

Views

Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Cf. A086264, A086899, A086900, A086906, A118998, A119002, A119009.

Extensions

a(8)-a(10) from Max Alekseyev, Jun 17 2025
Showing 1-5 of 5 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.