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.

A119007 Number of n X n real symmetric (+1,-1)-matrices having minimal determinant (=A119000(n)).

Original entry on oeis.org

1, 4, 16, 16, 416, 10240, 161280, 645120, 15482880, 402554880
Offset: 1

Views

Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Cf. A119000, A119003, A119005, A119006.

Extensions

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

A119001 Minimal permanent of real n X n symmetric (+1,-1) matrices.

Original entry on oeis.org

-1, 0, -6, -8, -120, -96, -5040, -4320, -362880
Offset: 1

Views

Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Cf. A118988, A118993, A118995, A118999, A119000, A119010.

Formula

For odd n, a(n) = -n!. - Max Alekseyev, Jun 18 2025

A118997 Number of real n X n symmetric (+1,-1) matrices with negative determinant.

Original entry on oeis.org

1, 4, 16, 80, 8448, 907904, 81949952, 13480664064, 12792558313472, 18963201072750592
Offset: 1

Views

Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Cf. A118999, A118992, A118994, A118996, A119000.

Formula

a(2n+1) = A118994(2n+1) = A118992(2n+1)/2. - Max Alekseyev, May 08 2009
a(n) = A118992(n) - A118994(n). - Max Alekseyev, Jun 12 2025

Extensions

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

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

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