login
A143889
Number of ways of placing kings with no more than 4 mutual attacks on an n X n chessboard symmetric about main diagonal.
2
1, 2, 7, 33, 202, 1671, 17279, 234724, 4081665, 92343898, 2711730350, 103991393887, 5218390436191
OFFSET
0,2
CROSSREFS
Sequence in context: A014623 A144005 A232690 * A350758 A241767 A222940
KEYWORD
nonn,more,hard
AUTHOR
R. H. Hardin, Sep 04 2008
STATUS
approved