OFFSET
4,1
COMMENTS
EXAMPLE
There are a(4) = 28 non-equivalent ways to place 7 points (X) on a 4 X 4 grid. Example:
. X X .
. . . X
X . . X
X X . .
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Heinrich Ludwig, Jan 12 2014
EXTENSIONS
a(13), a(14) from Heinrich Ludwig, Nov 16 2016
STATUS
approved