OFFSET
1,2
COMMENTS
Column 5 of A217891
EXAMPLE
Some solutions for n=4
..1....2....4....1....2....1....2....1....4....1....3....1....3....1....1....3
..1....2....2....1....3....2....2....1....3....1....4....3....2....4....1....4
..1....3....1....3....3....2....2....3....2....4....2....2....1....3....2....1
..4....1....1....2....1....4....1....4....1....3....1....2....1....2....2....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 14 2012
STATUS
approved