OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) - a(n-2) + 4*a(n-3) - 8*a(n-4) + 3*a(n-5) - 3*a(n-6) + 3*a(n-7) - 2*a(n-8) + a(n-9).
Empirical g.f.: x*(5 + 2*x - 4*x^2 - 8*x^3 + 2*x^4 - x^5 + x^6 - x^7 + x^8) / (1 - 3*x + x^2 - 4*x^3 + 8*x^4 - 3*x^5 + 3*x^6 - 3*x^7 + 2*x^8 - x^9). - Colin Barker, Sep 30 2018
EXAMPLE
Some solutions for n=7:
..1..1....0..1....0..0....0..1....0..0....0..0....0..0....0..0....1..1....0..1
..0..0....0..0....0..0....0..0....0..0....1..0....0..1....0..1....0..0....0..0
..0..0....1..0....1..1....0..1....1..0....1..0....0..0....1..1....0..0....0..1
..0..1....1..0....0..0....0..0....0..1....0..0....1..0....0..0....1..0....0..0
..1..0....0..0....0..0....0..1....0..0....1..1....0..0....0..0....0..1....0..1
..0..0....1..0....0..0....0..1....1..0....1..0....1..0....0..0....0..0....0..0
..0..0....1..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....1..0
..0..0....1..0....0..1....0..0....1..1....1..0....0..1....0..1....0..0....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 12 2013
STATUS
approved