OFFSET
1,1
COMMENTS
Column 2 of A205590.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) +24*a(n-2) +82*a(n-3) +83*a(n-4) -107*a(n-5) +30*a(n-6) +250*a(n-7).
Empirical g.f.: 2*x*(37 + 164*x + 397*x^2 + 286*x^3 - 541*x^4 + 165*x^5 + 1125*x^6) / (1 - 3*x - 24*x^2 - 82*x^3 - 83*x^4 + 107*x^5 - 30*x^6 - 250*x^7). - Colin Barker, Jun 12 2018
EXAMPLE
Some solutions for n=4:
..0..0..0....0..0..1....0..0..0....0..0..0....0..0..0....0..1..2....0..0..1
..1..0..0....0..2..2....0..1..2....0..0..1....1..0..0....0..2..0....2..0..2
..2..0..2....2..0..2....2..1..2....1..2..0....1..2..0....2..2..1....2..1..0
..2..0..1....2..0..1....1..0..2....1..2..1....2..1..0....0..1..2....2..2..2
..0..1..1....1..0..0....1..1..0....0..0..2....0..1..1....0..1..0....1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 29 2012
STATUS
approved