OFFSET
1,1
COMMENTS
Column 3 of A216937.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..21
EXAMPLE
Some solutions for n=3
......0.0.0..........0.0.1..........0.0.1..........0.1.1..........0.0.0
.....0.0.0.1........0.0.1.1........0.0.1.2........0.1.1.1........0.1.1.3
....0.1.1.1.1......1.1.1.3.3......0.0.1.2.3......1.1.1.1.3......0.1.1.3.3
.....1.2.2.3........2.2.3.3........2.2.3.3........1.2.2.3........1.2.3.3
......2.3.3..........2.3.3..........3.3.3..........3.3.3..........3.3.3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Sep 20 2012
STATUS
approved