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 1-4 of 4 results.

A143870 Number of ways of placing kings with no more than 1 mutual attack on an n X n chessboard.

Original entry on oeis.org

1, 2, 11, 91, 1462, 38483, 1755113, 140404442, 19400886875, 4764856837927, 2050537030592506, 1572046460892726633, 2133798146501117397613, 5167591018292995062973870, 22288638410038000574365307819, 171813750317653145879779979300275, 2366759768251260378737273078723819964
Offset: 0

Views

Author

R. H. Hardin, Sep 04 2008

Keywords

Examples

			Configurations of 0,1,2,3 or 4 kings on an 2 X 2 chessboard and the number of mutual attacks:
.. .. .. K. .K .. K. KK .K .K K. K. .K KK KK KK
.. K. .K .. .. KK K. .. .K K. .K KK KK .K K. KK
0  0  0  0  0  1  1  1  1  1  1  3  3  3  3  6
From 16 configurations is 11 with no more than 1 mutual attack, a(2)=11.

Links

Crossrefs

Cf. A143875, A143881, A143886.
Cf. A143871, A143872, A143873, A143874.
Diagonal of A268781.

Extensions

Example added by Vaclav Kotesovec, Oct 20 2014
Additional terms from R. H. Hardin, Feb 13 2016

A143875 Number of ways of placing kings with no more than 2 mutual attacks on an n X n chessboard.

Original entry on oeis.org

1, 2, 11, 155, 3280, 124511, 7623993, 795923016, 140176308483, 42642616703815
Offset: 0

Views

Author

R. H. Hardin, Sep 04 2008

Keywords

Crossrefs

Cf. A143870, A143881, A143886.
Cf. A143876, A143877, A143878, A143879, A143880.

A143881 Number of ways of placing kings with no more than 3 mutual attacks on an n X n chessboard.

Original entry on oeis.org

1, 2, 15, 207, 6084, 292607, 23511001, 3132847224, 693856861039, 259806377729539
Offset: 0

Views

Author

R. H. Hardin, Sep 04 2008

Keywords

Crossrefs

Cf. A143870, A143875, A143886.
Cf. A143882, A143883, A143884, A143885.

A143892 Number of ways of placing kings with no more than 4 mutual attacks on an n X n chessboard symmetric under 90-degree rotation.

Original entry on oeis.org

1, 2, 1, 5, 6, 29, 47, 300, 665, 5276, 15554, 160307, 632041, 8448701, 44021226
Offset: 0

Views

Author

R. H. Hardin, Sep 04 2008

Keywords

Examples

			Example: for n=3 the a(3)=5 solutions are
. . .   . . .   K . K   K . K   . K .
. . .   . K .   . . .   . K .   K . K
. . .   . . .   K . K   K . K   . K .

Crossrefs

Cf. A143870, A143875, A143881, A143886.
Cf. A143886, A143887, A143888, A143889, A143890, A143891, A143893.
Showing 1-4 of 4 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.