OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + a(n-2) + 2*a(n-3) + 6*a(n-4) - a(n-6) + a(n-7) - a(n-8) for n>9.
Empirical g.f.: x*(34 + 26*x + 62*x^2 + 81*x^3 - 44*x^4 - 13*x^5 + 14*x^6 - 23*x^7 + 6*x^8) / ((1 + x)*(1 - 2*x + x^2 - 3*x^3 - 3*x^4 + 3*x^5 - 2*x^6 + x^7)). - Colin Barker, Dec 27 2018
EXAMPLE
Some solutions for n=4:
..1..0..0....1..0..0....0..0..1....0..0..0....0..1..0....0..0..1....1..0..0
..0..1..0....0..0..0....0..0..0....0..0..0....0..1..0....0..0..0....0..1..0
..0..0..0....1..0..0....0..0..0....0..1..0....0..0..0....0..0..0....0..0..0
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..1..0....0..0..0
..0..1..0....0..0..0....0..0..1....0..0..0....0..0..0....0..1..0....1..0..0
..0..1..0....1..0..1....0..0..0....1..0..0....1..0..1....0..0..0....0..1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 10 2015
STATUS
approved