OFFSET
0,3
COMMENTS
This problem was stated in this fashion by R. Kenyon in the Domino Forum ([email protected]).
LINKS
Suresh Govindarajan, Table of n, a(n) for n = 0..60
S. Govindarajan, A. J. Guttmann and V. Subramanyan, On a square-ice analogue of plane partitions, arXiv:1607.01890 [cond-mat.stat-mech], 2016.
EXAMPLE
a(1)=1 as only the orange in the top layer can be removed. a(2)=4 as there are four oranges in the second layer and any one of them can be removed.
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Suresh Govindarajan, Jun 30 2016
STATUS
approved