OFFSET
1,3
COMMENTS
Column 2 of A221321
Solutions must alternate even-odd, and cannot have an odd number of those pairs for even n, so a(n)=0 for n modulo 4 = 2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
EXAMPLE
All solutions for n=5
..1....1....1....1....3
..0....0....0....2....0
..3....1....1....1....1
..0....0....2....0....0
..1....3....1....1....1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 10 2013
STATUS
approved