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 1-6 of 6 results.

A079137 Number of (undirected) Hamiltonian paths on the 4 X n knight graph.

Original entry on oeis.org

0, 0, 8, 0, 82, 744, 6378, 31088, 189688, 1213112, 6683852, 36486328, 201282470, 1083585304, 5706117458, 29819231288, 154430502724, 790787799376, 4014945695196, 20241304810488, 101336136490228, 504096313001272, 2493533648002492, 12270473056485396
Offset: 1

Views

Author

Eric W. Weisstein, Dec 28 2002

Keywords

References

  • Kraitchik, M. Mathematical Recreations. New York: W. W. Norton, p. 263, 1942.

Crossrefs

See A079312 for 4 times these numbers, A123935 for twice these numbers, A123936 for these numbers halved.

Extensions

More terms from André Pönitz (poenitz(AT)htwm.de), Jun 11 2003
Edited by N. J. A. Sloane, Oct 30 2006, following suggestions from Colin Rose
Terms a(22) and beyond from Andrew Howroyd, Jul 01 2017

A165134 Number of directed Hamiltonian paths in the n X n knight graph.

Original entry on oeis.org

1, 0, 0, 0, 1728, 6637920, 165575218320, 19591828170979904
Offset: 1

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Author

[No name given] (c.candide(AT)free.fr), Sep 04 2009

Keywords

Comments

Previous name was: Number of knight's paths visiting each square of an n X n chessboard exactly once.

Examples

			From _Gheorghe Coserea_, Oct 08 2016: (Start)
For n=5 the numbers in the table below give the number of knight's paths starting at the respective position on the 5 X 5 chessboard.  In total there are a(5) = 304*4 + 56*8 + 64 = 1728 solutions.
    [1]  [2]  [3]  [4]  [5]
[1] 304    0   56    0  304
[2]   0   56    0   56    0
[3]  56    0   64    0   56
[4]   0   56    0   56    0
[5] 304    0   56    0  304
(End)
		

Crossrefs

Cf. Undirected Hamiltonian paths: A169696 (3 X n), A079137 (4 X n), A083386 (5 X n), A306281 (6 X n), A306283 (7 X n), A308131 (n X n).

Extensions

a(7) from Guenter Stertenbrink, added by Alex Chernov, Sep 01 2013
a(1)=1, a(2)=0 prepended by Max Alekseyev, Sep 22 2013
a(8) from Alex Chernov, May 10 2014
Name made more precise by Eric W. Weisstein, Apr 14 2019

A118067 Number of (directed) Hamiltonian paths in the 3 X n knight graph.

Original entry on oeis.org

0, 0, 0, 16, 0, 0, 104, 792, 1120, 6096, 21344, 114496, 257728, 1292544, 3677568, 17273760, 46801984, 211731376, 611507360, 2645699504, 7725948608, 32451640000, 97488160384, 397346625760, 1214082434112, 4835168968464, 15039729265856, 58641619298000
Offset: 1

Views

Author

Colin Rose, May 11 2006

Keywords

Comments

1. Jelliss computes the number of tour diagrams (which is equal to half the number of tours). 2. Sequence A079137 computes the number of tour DIAGRAMS for a 4 X k board (again, equal to half the number of tours). 3. Kraitchik (1942) incorrectly reports 376 tour diagrams for the 3 X 8 case; the correct number is 396 (i.e., 792 tours) [cf. Rose, Jelliss].

References

  • Kraitchik, M., Mathematical Recreations. New York: W. W. Norton, pp. 264-5, 1942.

Crossrefs

Programs

  • Mathematica
    Mathematica notebook available at: http://www.tri.org.au/knightframe.html

Formula

a(n) = 2 * A169696(n). - Andrew Howroyd, Jul 01 2017

Extensions

a(13) from Eric W. Weisstein, Mar 13 2009
a(14)-a(21) from Seiichi Manyama, Apr 25 2016
a(22)-a(28) from Andrew Howroyd, Jul 01 2017

A306281 Number of (undirected) Hamiltonian paths on the 6 X n knight graph.

Original entry on oeis.org

0, 0, 0, 744, 18784, 3318960, 389969466, 24964893804, 1770631206422, 143827657320448, 10668015492137018, 763955912402146956, 55382275594728895388, 4008456113318585117624, 285329658478008271167456, 20203324505809248032547768, 1425847547641332606081597198, 100103728161914529291271962728
Offset: 1

Views

Author

Seiichi Manyama, Feb 03 2019

Keywords

Crossrefs

Cf. A169696 (3 X n), A079137 (4 X n), A083386 (5 X n), this sequence (6 X n), A306283 (7 X n), A308131 (n X n).

Extensions

a(8)-a(11) from Andrew Howroyd, Oct 14 2019
a(12) from Valentin Gubarev, Dec 23 2024
a(13)-a(18) from Andrew Howroyd, Dec 26 2024

A306283 Number of (undirected) Hamiltonian paths on the 7 X n knight graph.

Original entry on oeis.org

0, 0, 52, 6378, 622868, 389969466, 82787609160, 20666425060328, 2903212163753000, 1025241126020698238
Offset: 1

Views

Author

Seiichi Manyama, Feb 03 2019

Keywords

Crossrefs

Cf. A169696 (3 X n), A079137 (4 X n), A083386 (5 X n), A306281 (6 X n), this sequence (7 X n).

Extensions

a(8)-a(10) from Valentin Gubarev, Dec 23 2024

A308131 Number of (undirected) Hamiltonian paths in the n X n knight graph.

Original entry on oeis.org

0, 0, 0, 0, 864, 3318960, 82787609160, 9795914085489952
Offset: 1

Views

Author

Eric W. Weisstein, May 14 2019

Keywords

Crossrefs

Cf. A165134, A169696 (3 X n), A079137 (4 X n), A083386 (5 X n), A306281 (6 X n), A306283 (7 X n).

Formula

a(n) = A165134(n)/2.
Showing 1-6 of 6 results.