OFFSET
1,5
COMMENTS
Conjecture: a(n) = A321532(n)/8 for n >= 4.
EXAMPLE
For n = 5, the a(5) = 2 essentially different configurations of nonattacking rooks with the maximal number of directions between them are given by the following two chessboards:
+---+---+---+---+---+
5| X | | | | |
+---+---+---+---+---+
4| | | X | | |
+---+---+---+---+---+
3| | | | X | |
+---+---+---+---+---+
2| | | | | X |
+---+---+---+---+---+
1| | X | | | |
+---+---+---+---+---+
A B C D E
+---+---+---+---+---+
5| X | | | | |
+---+---+---+---+---+
4| | | | X | |
+---+---+---+---+---+
3| | | X | | |
+---+---+---+---+---+
2| | | | | X |
+---+---+---+---+---+
1| | X | | | |
+---+---+---+---+---+
A B C D E
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Peter Kagey, Nov 12 2018
STATUS
approved