OFFSET
1,1
COMMENTS
Column 3 of A207254.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 4*a(n-2) + 7*a(n-4) + 8*a(n-5) - a(n-8).
Empirical g.f.: 2*x*(3 + 12*x + 3*x^2 + 11*x^3 + 21*x^4 - 3*x^5 - 3*x^7) / (1 - 2*x - 4*x^2 - 7*x^4 - 8*x^5 + x^8). - Colin Barker, Feb 20 2018
EXAMPLE
Some solutions for n=4:
..0..0..0....1..0..0....0..1..0....1..1..0....1..0..0....1..1..0....0..0..0
..0..1..1....0..0..0....1..0..0....1..0..0....1..0..0....0..0..0....1..0..0
..1..1..1....0..0..0....1..0..0....1..0..0....1..0..0....0..0..0....1..1..1
..1..0..0....0..1..0....1..1..0....0..1..1....1..0..0....1..0..0....0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 16 2012
STATUS
approved