OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + a(n-3) + 2*a(n-4) - a(n-5) for n>6.
Empirical g.f.: x*(72 - 171*x + 65*x^2 + 87*x^3 - 59*x^4 + 3*x^5) / ((1 - x)^3*(1 - x - x^2)). - Colin Barker, Nov 26 2018
EXAMPLE
Some solutions for n=4:
..0..0..0..1..0....0..0..0..0..0....0..0..1..0..0....0..0..0..0..1
..1..0..0..1..0....0..0..0..0..0....0..0..1..0..0....0..0..0..0..1
..1..0..0..1..0....0..0..0..0..0....0..0..1..0..0....0..0..0..0..1
..1..0..0..1..0....0..0..0..0..0....1..0..1..0..0....0..0..0..0..1
..1..0..0..1..0....1..1..1..0..0....1..0..1..0..0....1..0..0..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 30 2014
STATUS
approved