A143870 Number of ways of placing kings with no more than 1 mutual attack on an n X n chessboard.
1, 2, 11, 91, 1462, 38483, 1755113, 140404442, 19400886875, 4764856837927, 2050537030592506, 1572046460892726633, 2133798146501117397613, 5167591018292995062973870, 22288638410038000574365307819, 171813750317653145879779979300275, 2366759768251260378737273078723819964
Offset: 0
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
- R. H. Hardin, Table of n, a(n) for n = 0..26
Crossrefs
Extensions
Example added by Vaclav Kotesovec, Oct 20 2014
Additional terms from R. H. Hardin, Feb 13 2016