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.

A305570 Number of diagonal Latin squares of order n with the first row in order and at least one orthogonal diagonal mate.

Original entry on oeis.org

1, 0, 0, 2, 4, 0, 256, 632064, 95024976
Offset: 1

Views

Author

Eduard I. Vatutin, Jun 05 2018

Keywords

Crossrefs

Formula

a(n) = A305571(n) / n!.
a(n) = A274171(n) - A305568(n).

Extensions

Name clarified by Andrew Howroyd, Oct 19 2020
a(9) added by Eduard I. Vatutin, Dec 22 2020

A309210 Number of main classes of extended self-orthogonal diagonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 1, 1, 0, 5, 23, 18865, 33240
Offset: 1

Views

Author

Eduard I. Vatutin, Aug 09 2019

Keywords

Comments

A self-orthogonal diagonal Latin square (SODLS) is a diagonal Latin square orthogonal to its transpose. An extended self-orthogonal diagonal Latin square (ESODLS) is a diagonal Latin square that has an orthogonal diagonal Latin square from the same main class. SODLS is a special case of ESODLS.
A333366(n) <= A329685(n) <= a(n) <= A330391(n). - Eduard I. Vatutin, Jun 07 2020
a(10) >= 33240. - Eduard I. Vatutin, Jul 09 2020

Examples

			The diagonal Latin square
  0 1 2 3 4 5 6 7 8 9
  1 2 0 4 5 7 9 8 6 3
  5 0 1 6 3 9 8 2 4 7
  9 3 5 8 2 1 7 4 0 6
  4 6 3 5 7 8 0 9 2 1
  8 4 6 9 1 3 2 5 7 0
  7 8 9 0 6 4 5 1 3 2
  2 9 4 7 8 0 3 6 1 5
  6 5 7 1 0 2 4 3 9 8
  3 7 8 2 9 6 1 0 5 4
has the orthogonal diagonal Latin square
  0 1 2 3 4 5 6 7 8 9
  3 5 9 8 6 2 0 1 4 7
  4 3 8 7 2 1 9 0 5 6
  6 9 3 4 8 0 1 2 7 5
  7 2 0 1 9 3 5 8 6 4
  2 0 1 5 7 6 4 9 3 8
  8 6 4 2 0 9 7 5 1 3
  1 7 6 0 5 4 8 3 9 2
  9 8 5 6 1 7 3 4 2 0
  5 4 7 9 3 8 2 6 0 1
from the same main class.
		

Crossrefs

Extensions

a(9) added by Eduard I. Vatutin, Dec 08 2020
a(10) added by Eduard I. Vatutin, Oleg S. Zaikin, Jan 30 2025

A329685 Number of main classes of self-orthogonal diagonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 1, 1, 0, 2, 8, 470, 30502
Offset: 1

Views

Author

Eduard I. Vatutin, Feb 25 2020

Keywords

Comments

A self-orthogonal diagonal Latin square is a diagonal Latin square orthogonal to its transpose.
A333366(n) <= a(n) <= A309210(n) <= A330391(n). - Eduard I. Vatutin, Apr 26 2020

Examples

			0 1 2 3 4 5 6 7 8 9
5 2 0 9 7 8 1 4 6 3
9 5 7 1 8 6 4 3 0 2
7 8 6 4 9 2 5 1 3 0
8 9 5 0 3 4 2 6 7 1
3 6 9 5 2 1 7 0 4 8
4 3 1 7 6 0 8 2 9 5
6 7 8 2 5 3 0 9 1 4
2 0 4 6 1 9 3 8 5 7
1 4 3 8 0 7 9 5 2 6
		

Crossrefs

Extensions

a(9) from Eduard I. Vatutin, Mar 12 2020
a(10) from Eduard I. Vatutin, Mar 14 2020
a(10) corrected by Natalia Makarova, Apr 10 2020

A333366 Number of main classes of doubly self-orthogonal diagonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 1, 1, 0, 2, 8, 88, 0
Offset: 1

Views

Author

Eduard I. Vatutin, Mar 17 2020

Keywords

Comments

A doubly self-orthogonal diagonal Latin square (DSODLS) is a diagonal Latin square orthogonal to its transpose and antitranspose.
a(n) <= A329685(n) <= A309210(n) <= A330391(n). - Eduard I. Vatutin, Jun 01 2020

Examples

			0 1 2 3 4 5 6 7 8
2 4 3 0 7 6 8 1 5
4 6 7 1 8 2 3 5 0
8 3 5 6 0 7 1 2 4
7 8 1 4 5 3 0 6 2
3 7 0 2 1 8 5 4 6
1 5 4 7 6 0 2 8 3
5 0 6 8 2 1 4 3 7
6 2 8 5 3 4 7 0 1
		

Crossrefs

Extensions

a(10) = 0 is established by Lu et al. (2011).

A337309 Number of main classes of bachelor diagonal Latin squares of order n.

Original entry on oeis.org

0, 0, 0, 0, 1, 2, 967, 4871991, 3292326080087
Offset: 1

Views

Author

Eduard I. Vatutin, Aug 22 2020

Keywords

Comments

A bachelor diagonal Latin square is one with no orthogonal mate.

Crossrefs

Formula

a(n) = A287764(n) - A330391(n).

Extensions

a(9) added by Eduard I. Vatutin, Dec 08 2020
Showing 1-5 of 5 results.