OFFSET
1,1
COMMENTS
Column 4 of A231137
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 175*a(n-2) -4017*a(n-4) +34311*a(n-6) -146236*a(n-8) +322472*a(n-10) -291040*a(n-12) +116032*a(n-14) -24064*a(n-16) +1024*a(n-18)
EXAMPLE
Some solutions for n=4
..x..0..x..1..x....x..0..x..1..x....x..0..x..1..x....x..0..x..0..x
..0..x..2..x..0....1..x..0..x..2....2..x..0..x..1....0..x..1..x..2
..x..1..x..0..x....x..2..x..2..x....x..2..x..0..x....x..2..x..2..x
..1..x..1..x..1....0..x..1..x..0....1..x..1..x..2....1..x..1..x..1
..x..2..x..0..x....x..0..x..2..x....x..2..x..1..x....x..2..x..0..x
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 04 2013
STATUS
approved