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.

A345370 a(n) is the number of distinct numbers of diagonal transversals that a diagonal Latin square of order n can have.

Original entry on oeis.org

1, 0, 0, 1, 2, 2, 14, 47, 182
Offset: 1

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Author

Eduard I. Vatutin, Jun 16 2021

Keywords

Comments

a(n) <= A287648(n) - A287647(n) + 1.
a(n) <= A287764(n).
Conjecture: a(12) = A287648(12) - A287647(12) + 1. - Natalia Makarova, Oct 26 2021
a(10) >= 736, a(11) >= 1344, a(12) >= 17693, a(13) >= 18241, a(14) >= 294053, a(15) >= 1958394, a(16) >= 13715. - Eduard I. Vatutin, Oct 29 2021, updated Mar 02 2025

Examples

			For n=7 the number of diagonal transversals that a diagonal Latin square of order 7 may have is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, or 27. Since there are 14 distinct values, a(7)=14.
		

Crossrefs

Extensions

a(8) added by Eduard I. Vatutin, Jul 15 2021
a(9) added by Eduard I. Vatutin, Oct 20 2022

A350585 a(n) is the number of distinct numbers of transversals that an orthogonal diagonal Latin square of order n can have.

Original entry on oeis.org

1, 0, 0, 1, 1, 0, 4, 25, 295
Offset: 1

Views

Author

Eduard I. Vatutin, Mar 27 2022

Keywords

Comments

An orthogonal diagonal Latin square is a diagonal Latin square with at least one orthogonal diagonal mate. Since all orthogonal diagonal Latin squares are diagonal Latin squares, a(n) <= A344105(n).
a(10) >= 193, a(11) >= 3588, a(12) >= 10465. - updated by Eduard I. Vatutin, Jan 29 2023

Examples

			For n=8 the number of transversals that an orthogonal diagonal Latin square of order 8 may have is 16, 32, 40, 48, 52, 56, 60, 64, 68, 72, 76, 80, 88, 96, 112, 128, 132, 144, 160, 168, 192, 224, 256, 320, or 384. Since there are 25 distinct values, a(8)=25.
		

Crossrefs

A360220 Maximum number of diagonal transversals in an orthogonal diagonal Latin square of order n.

Original entry on oeis.org

1, 0, 0, 4, 5, 0, 27, 120, 333
Offset: 1

Views

Author

Eduard I. Vatutin, Jan 30 2023

Keywords

Comments

An orthogonal diagonal Latin square is a diagonal Latin square that has at least one orthogonal diagonal mate.
a(10) >= 866, a(11) >= 4828, a(12) >= 30192, a(13) >= 131106, a(17) >= 204995269, a(19) >= 11254190082.
For most orders n, at least one diagonal Latin square with the maximal number of diagonal transversals has an orthogonal mate and A287648(n) = a(n). Known exceptions: n=6 and n=10. - Eduard I. Vatutin, Feb 17 2023
Every orthogonal diagonal Latin square is a diagonal Latin square, so A287647(n) <= A354068(n) <= a(n) <= A287648(n). - Eduard I. Vatutin, Mar 04 2023

Crossrefs

A354068 Minimum number of diagonal transversals in an orthogonal diagonal Latin square of order n.

Original entry on oeis.org

1, 0, 0, 4, 5, 0, 8, 8, 14
Offset: 1

Views

Author

Eduard I. Vatutin, May 16 2022

Keywords

Comments

An orthogonal diagonal Latin square is a diagonal Latin square with at least one orthogonal diagonal mate.
a(10) <= 60, a(11) <= 279, a(12) <= 588, a(13) <= 9610.
Every orthogonal diagonal Latin square is a diagonal Latin square, so A287647(n) <= a(n) <= A360220(n) <= A287648(n). - Eduard I. Vatutin, Mar 03 2023

Examples

			One of the best orthogonal diagonal Latin squares of order n=9
  0 1 2 3 4 5 6 7 8
  1 2 3 8 6 4 7 0 5
  5 4 6 0 7 8 3 1 2
  7 3 1 5 2 6 0 8 4
  8 7 4 6 1 2 5 3 0
  3 0 5 4 8 7 1 2 6
  4 6 7 2 3 0 8 5 1
  6 5 8 1 0 3 2 4 7
  2 8 0 7 5 1 4 6 3
has orthogonal diagonal mate
  0 1 2 3 4 5 6 7 8
  2 3 8 7 5 6 4 1 0
  1 5 4 8 6 0 2 3 7
  8 7 0 6 1 3 5 4 2
  5 0 1 2 7 8 3 6 4
  4 6 7 0 3 2 8 5 1
  3 8 5 4 0 7 1 2 6
  7 4 6 5 2 1 0 8 3
  6 2 3 1 8 4 7 0 5
and 14 diagonal transversals, which is the minimal number, so a(9)=14.
		

Crossrefs

A354050 a(n) is the number of distinct numbers of intercalates that an orthogonal diagonal Latin square of order n can have.

Original entry on oeis.org

0, 0, 0, 1, 1, 0, 3, 26, 55
Offset: 1

Views

Author

Eduard I. Vatutin, May 16 2022

Keywords

Comments

An orthogonal diagonal Latin square is a diagonal Latin square with at least one orthogonal diagonal mate. Since all orthogonal diagonal Latin squares are diagonal Latin squares, a(n) <= A345760(n).
a(10) >= 74, a(11) >= 76, a(12) >= 190. - updated by Eduard I. Vatutin, Mar 01 2025

Examples

			For n=8 the number of intercalates that an orthogonal diagonal Latin square of order 8 may have is 2, 4, 8, 9, 10, 11, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 36, 40, 44, 48, 52, 56, 64, 80, or 112. Since there are 26 distinct values, a(8)=26.
		

Crossrefs

Showing 1-5 of 5 results.