OFFSET
2,1
EXAMPLE
One solution for n=7
...1.1.2.2.2.2.2..............
.....1.1.1.1.2.2.2............
.......2.2.2.2.3.2.3..........
.........2.2.3.3.2.3.3........
...........2.3.3.2.3.3.4......
.............3.3.2.3.4.4.4....
...............3.3.3.3.3.4.4..
.................3.4.4.4.4.4.4
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Sep 17 2009
STATUS
approved