OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 19*a(n-2) - 38*a(n-3) - 136*a(n-4) + 272*a(n-5) + 456*a(n-6) - 912*a(n-7) - 720*a(n-8) + 1440*a(n-9) + 432*a(n-10) - 864*a(n-11).
Empirical g.f.: 2*x*(23 + 38*x - 304*x^2 - 370*x^3 + 1656*x^4 + 1266*x^5 - 4716*x^6 - 1800*x^7 + 6912*x^8 + 1080*x^9 - 3888*x^10) / ((1 - 2*x)*(1 - 2*x^2)^2*(1 - 3*x^2)*(1 - 6*x^2)^2). - Colin Barker, Nov 29 2018
EXAMPLE
Some solutions for n=4:
..0..1....2..0....0..1....0..0....0..2....2..0....2..0....0..2....0..0....1..0
..1..0....2..1....0..2....0..2....0..1....1..0....0..0....1..0....1..2....2..2
..1..0....2..2....0..1....0..0....2..2....2..0....0..2....2..0....0..0....0..1
..1..1....2..1....1..1....0..2....0..1....1..2....0..1....1..0....2..1....2..2
..2..1....2..2....1..2....1..2....2..2....0..2....2..2....0..2....1..1....1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 02 2014
STATUS
approved