OFFSET
3,1
COMMENTS
EXAMPLE
There are a(3) = 2 non-equivalent ways to arrange 4 indistinguishable points (x) on a triangular grid of side 3:
x .
x x x x
. x . x . x
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Heinrich Ludwig, Dec 30 2013
EXTENSIONS
a(14)-a(17) from Heinrich Ludwig, Apr 19 2016
STATUS
approved