OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
Robert Israel, Maple-assisted proof of empirical formula
FORMULA
Empirical: a(n) = 5*a(n-1) +8*a(n-2) -20*a(n-3) -23*a(n-4) -52*a(n-5) +25*a(n-6) +254*a(n-7) +62*a(n-8) -134*a(n-9) -88*a(n-10) -360*a(n-11) +176*a(n-12) -168*a(n-13) +184*a(n-14).
Empirical formula confirmed by Robert Israel, Jun 28 2018 (see link).
EXAMPLE
Some solutions for n=5
..1..2....2..0....1..1....0..1....2..0....2..2....2..1....0..0....0..1....2..1
..2..2....0..0....2..2....1..0....0..2....0..1....2..2....1..1....0..0....2..2
..0..1....0..0....1..2....0..1....2..0....0..2....0..0....0..0....2..2....1..0
..0..2....1..2....0..0....0..1....1..2....1..0....1..1....1..0....2..2....0..0
..0..0....2..2....2..0....0..0....2..2....2..2....1..0....2..2....2..1....1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 19 2011
STATUS
approved