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.

A299784 Maximum size of a main class for diagonal Latin squares of order n with the first row in ascending order.

Original entry on oeis.org

1, 0, 0, 2, 4, 96, 192, 1536, 1536, 15360, 15360, 184320, 184320, 2580480, 2580480
Offset: 1

Views

Author

Eduard I. Vatutin, Jan 21 2019

Keywords

Comments

a(n) <= 2^m * m! * 4, where m = floor(n/2).
It seems that a(n) = 2^m * m! * 4 for all n > 6. - Eduard I. Vatutin, Jun 08 2020
0 <= A299783(n) <= a(n). - Eduard I. Vatutin, Jun 08 2020

Examples

			From _Eduard I. Vatutin_, May 30 2021: (Start)
The following DLS of order 9 has a main class with cardinality 1536:
  0 1 2 3 4 5 6 7 8
  1 2 0 4 8 6 5 3 7
  7 4 5 8 0 3 2 6 1
  5 8 7 6 1 0 3 2 4
  8 0 3 2 7 1 4 5 6
  3 7 8 5 6 4 1 0 2
  6 3 1 7 5 2 8 4 0
  2 6 4 0 3 8 7 1 5
  4 5 6 1 2 7 0 8 3
The following DLS of order 10 has a main class with cardinality 15360:
  0 1 2 3 4 5 6 7 8 9
  1 2 0 4 5 3 9 8 6 7
  3 5 6 1 8 7 4 0 9 2
  9 4 7 8 3 2 1 6 0 5
  2 7 3 0 9 8 5 1 4 6
  6 8 5 9 2 4 7 3 1 0
  4 6 9 7 0 1 3 2 5 8
  7 0 4 6 1 9 8 5 2 3
  8 3 1 5 6 0 2 9 7 4
  5 9 8 2 7 6 0 4 3 1
(End)
		

Crossrefs

Formula

a(n) = A299787(n) / n!.
From Eduard I. Vatutin, May 30 2021: (Start)
A299783(n) = a(n) for 1 <= n <= 5.
A299783(6)*3 = a(6).
A299783(7)*6 = a(7).
A299783(8)*16 = a(8).
A299783(9)*32 <= a(9).
A299783(10)*10 <= a(10).
A299783(11)*10 <= a(11).
A299783(12)*4 <= a(12).
A299783(13)*24 <= a(13). (End)

Extensions

a(9)-a(10) from Eduard I. Vatutin, Mar 15 2020
a(11)-a(15) from Eduard I. Vatutin, Jun 08 2020

A299783 Minimum size of a main class for diagonal Latin squares of order n with the first row in ascending order.

Original entry on oeis.org

1, 0, 0, 2, 4, 32, 32, 96
Offset: 1

Views

Author

Eduard I. Vatutin, Jan 21 2019

Keywords

Comments

a(9) <= 48; a(10) <= 1536, a(11) <= 1536, a(12) <= 46080, a(13) <= 7680. - Eduard I. Vatutin, Oct 05 2020, updated Apr 08 2025

Examples

			From _Eduard I. Vatutin_, Oct 05 2020: (Start)
The following DLS of order 9 has a main class with cardinality 48:
  0 1 2 3 4 5 6 7 8
  2 4 3 0 7 6 8 1 5
  6 2 8 5 3 4 7 0 1
  4 6 7 1 8 2 3 5 0
  1 5 4 7 6 0 2 8 3
  7 8 1 4 5 3 0 6 2
  3 7 0 2 1 8 5 4 6
  8 3 5 6 0 7 1 2 4
  5 0 6 8 2 1 4 3 7
The following DLS of order 10 has a main class with cardinality 7680:
  0 1 2 3 4 5 6 7 8 9
  1 2 0 4 3 6 5 9 7 8
  2 0 3 5 8 1 4 6 9 7
  4 6 9 7 1 8 2 0 3 5
  9 7 8 6 5 4 3 1 2 0
  3 4 7 8 0 9 1 2 5 6
  6 9 4 1 7 2 8 5 0 3
  7 8 5 0 6 3 9 4 1 2
  5 3 1 9 2 7 0 8 6 4
  8 5 6 2 9 0 7 3 4 1
(End)
		

Crossrefs

Formula

a(n) = A299785(n) / n!.
0 <= a(n) <= A299784(n). - Eduard I. Vatutin, Jun 08 2020
From Eduard I. Vatutin, added May 30 2021, updated Apr 08 2025: (Start)
a(n) = A299784(n) for 1 <= n <= 5.
a(6)*3 = A299784(6).
a(7)*6 = A299784(7).
a(8)*16 = A299784(8).
a(9)*32 <= A299784(9).
a(10)*10 <= A299784(10).
a(11)*10 <= A299784(11).
a(12)*4 <= A299784(12).
a(13)*24 <= A299784(13). (End)

A299785 Minimum size of a main class for diagonal Latin squares of order n.

Original entry on oeis.org

1, 0, 0, 48, 480, 23040, 161280, 3870720
Offset: 1

Views

Author

Eduard I. Vatutin, Jan 21 2019

Keywords

Comments

0 <= a(n) <= A299787(n). - Eduard I. Vatutin, Jun 08 2020
a(9) <= 17418240; a(10) <= 27869184000. - Eduard I. Vatutin, Oct 05 2020
a(11) <= 61312204800, a(12) <= 22072393728000, a(13) <= 47823519744000. - Eduard I. Vatutin, May 31 2021

Examples

			From _Eduard I. Vatutin_, Oct 05 2020: (Start)
The following DLS of order 9 has a main class with cardinality 48*9! = 17418240:
  0 1 2 3 4 5 6 7 8
  2 4 3 0 7 6 8 1 5
  6 2 8 5 3 4 7 0 1
  4 6 7 1 8 2 3 5 0
  1 5 4 7 6 0 2 8 3
  7 8 1 4 5 3 0 6 2
  3 7 0 2 1 8 5 4 6
  8 3 5 6 0 7 1 2 4
  5 0 6 8 2 1 4 3 7
The following DLS of order 10 has a main class with cardinality 7680*10! = 27869184000:
  0 1 2 3 4 5 6 7 8 9
  1 2 0 4 3 6 5 9 7 8
  2 0 3 5 8 1 4 6 9 7
  4 6 9 7 1 8 2 0 3 5
  9 7 8 6 5 4 3 1 2 0
  3 4 7 8 0 9 1 2 5 6
  6 9 4 1 7 2 8 5 0 3
  7 8 5 0 6 3 9 4 1 2
  5 3 1 9 2 7 0 8 6 4
  8 5 6 2 9 0 7 3 4 1
(End)
		

Crossrefs

Formula

a(n) = A299783(n) * n!.
From Eduard I. Vatutin, May 31 2021: (Start)
a(n) = A299787(n) for 1 <= n <= 5.
a(6) = A299787(6)/3.
a(7) = A299787(7)/6.
a(8) = A299787(8)/16.
a(9) = A299787(9)/32.
a(10) = A299787(10)/2.
a(11) = A299787(11)/10.
a(12) = A299787(12)/4.
a(13) = A299787(13)/24. (End)
Showing 1-3 of 3 results.