OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 2*a(n-2) + 2*a(n-3) + 6*a(n-4) - 8*a(n-5) - 3*a(n-6) - 4*a(n-7) - 10*a(n-8) - 4*a(n-9) + 8*a(n-10) for n>11.
Empirical g.f.: x*(40 + 34*x + 29*x^2 - 2*x^3 - 213*x^4 - 37*x^5 - 90*x^6 - 122*x^7 + 72*x^8 + 152*x^9 - 60*x^10) / (1 - x - 2*x^2 - 2*x^3 - 6*x^4 + 8*x^5 + 3*x^6 + 4*x^7 + 10*x^8 + 4*x^9 - 8*x^10). - Colin Barker, Dec 28 2018
EXAMPLE
Some solutions for n=4:
..0..0..0....1..0..0....1..0..1....1..0..0....0..0..0....0..0..1....0..0..0
..0..0..1....0..1..0....0..1..0....0..0..0....0..0..1....0..1..0....0..0..1
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..1..0
..1..0..0....0..0..0....0..0..0....0..1..0....1..0..0....0..0..0....0..0..0
..0..1..0....0..1..0....0..1..0....0..1..0....0..0..0....0..1..0....0..1..0
..0..0..1....0..1..0....1..0..1....0..1..0....0..0..0....0..0..1....1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 17 2015
STATUS
approved