OFFSET
1,3
COMMENTS
Plane partitions seen as 3-dimensional-objects can have a threefold symmetry axis.
EXAMPLE
n=3 gives 2 forms: {{3}}={{1,1,1}}={{1},{1},{1}} and {{2,1}}={{1,1},{1}}={{2},{1}}.
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Edited by N. J. A. Sloane, Oct 26 2008 at the suggestion of R. J. Mathar.
STATUS
approved