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.

A190393 Number of ways to place n nonattacking nightriders on an n X n toroidal board.

Original entry on oeis.org

1, 2, 6, 24, 120, 144, 28, 1408, 2025, 86400, 1782, 1092096, 4186, 31360, 241920000, 23953408, 140692, 114108912, 1092690
Offset: 1

Views

Author

Vaclav Kotesovec, May 10 2011

Keywords

Comments

A nightrider is a fairy chess piece that can move (proportionate to how a knight moves) in any direction.

Crossrefs

Extensions

Terms a(16)-a(17) from Vaclav Kotesovec, May 14 2011
Terms a(18)-a(19) from Vaclav Kotesovec, May 28 2011

A190394 Maximum number of nonattacking nightriders on an n X n board.

Original entry on oeis.org

1, 4, 5, 8, 10, 16, 17, 20, 21, 24, 26, 32, 33, 36, 39, 42, 45, 48, 51, 54, 58, 64, 65, 66, 68, 72, 75, 80, 81, 84, 87, 90, 93
Offset: 1

Views

Author

Vaclav Kotesovec, May 10 2011

Keywords

Comments

A nightrider is a fairy chess piece that can move any distance in a direction specified by a knight move.
Maximum number of nonattacking nightriders on an n X n toroidal board is n.

Examples

			From _Rob Pratt_, Jul 24 2015: (Start)
a(20) = 54:
  XX--XXXX---X------XX
  XX---------X--XX--XX
  --------------------
  ---X----------------
  X-----------------X-
  X-----------------X-
  X-------------------
  X---------X---------
  ------------------XX
  ------------X-------
  -------X------------
  XX------------------
  ---------X---------X
  -------------------X
  -X-----------------X
  -X-----------------X
  ----------------X---
  --------------------
  XX--XX--X---------XX
  XX------X---XXXX--XX
(End)
		

Crossrefs

Formula

2n <= a(n) <= 3n-2, for n > 3.
a(n) >= 24*floor((n+4)/10)-8, for n >= 6. - Vaclav Kotesovec, Apr 01 2012

Extensions

Terms a(11)-a(16) from Vaclav Kotesovec, May 13 2011
Terms a(17)-a(19) from Vaclav Kotesovec, Apr 01 2012
a(20) from Rob Pratt, Jul 24 2015
a(21)-a(32) from Paul Tabatabai, Nov 06 2018
a(33) from Andy Huchala, Mar 30 2024

A196811 Number of ways to place 3 nonattacking nightriders on an n X n cylindrical board.

Original entry on oeis.org

0, 0, 6, 144, 600, 1992, 4592, 15616, 31788, 74840, 122210, 251184, 384826, 647696, 1085190, 1616384, 2308872, 3449880, 4783326, 7052400, 9253734, 12454640, 16453096, 22180992, 28552450, 36216544, 46089162, 58449104, 72061346, 91140000, 109813780, 135448576
Offset: 1

Views

Author

Vaclav Kotesovec, Oct 06 2011

Keywords

Comments

A nightrider is a fairy chess piece that can move (proportionate to how a knight moves) in any direction.

Crossrefs

A196813 Number of ways to place 3 nonattacking nightriders on an n X n toroidal board.

Original entry on oeis.org

0, 0, 6, 96, 600, 1392, 2156, 10624, 22410, 62400, 82280, 210336, 280540, 495488, 955950, 1332736, 1844976, 2924640, 3933456, 6319200, 7954170, 10648000, 14081980, 19826304, 25502500, 31809856, 41037354, 52338272, 63979916, 84001200, 98348740, 123033600
Offset: 1

Views

Author

Vaclav Kotesovec, Oct 06 2011

Keywords

Comments

A nightrider is a fairy chess piece that can move (proportionate to how a knight moves) in any direction.

Crossrefs

A196814 Number of ways to place n nonattacking nightriders on an n X n cylindrical board.

Original entry on oeis.org

1, 4, 6, 84, 120, 784, 280, 40816, 13806, 1361706, 110990, 142633176, 4263454, 197730660, 9246172320
Offset: 1

Views

Author

Vaclav Kotesovec, Oct 06 2011

Keywords

Crossrefs

Showing 1-5 of 5 results.