OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*a(n-1) - 12*a(n-2) + 5*a(n-3) + 13*a(n-4) - 16*a(n-5) + 2*a(n-6) + 5*a(n-7) - 2*a(n-8).
Empirical g.f.: 2*x*(72 - 234*x + 171*x^2 + 259*x^3 - 420*x^4 + 70*x^5 + 148*x^6 - 64*x^7) / ((1 - x)^4*(1 + x)*(1 - 2*x)*(1 - x - x^2)). - Colin Barker, Nov 20 2018
EXAMPLE
Some solutions for n=4:
..0..1..0..0..0....0..0..0..0..1....0..0..0..0..1....0..0..0..1..0
..0..1..0..0..1....0..0..0..1..0....0..0..0..0..1....1..1..1..0..1
..0..1..0..0..1....0..0..0..1..0....0..0..0..0..1....1..1..1..1..0
..0..1..0..1..0....0..0..0..1..0....1..1..1..1..0....1..1..1..1..1
..0..1..0..1..0....0..0..0..1..1....1..1..1..1..0....1..1..1..1..1
..1..0..1..0..1....0..0..0..1..1....1..1..1..1..1....1..1..1..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 27 2014
STATUS
approved