OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 13*a(n-1) - 36*a(n-2) + 29*a(n-3) - 5*a(n-4) for n>5.
Empirical g.f.: x*(5 - 15*x + 12*x^2 - 12*x^3 + 2*x^4) / ((1 - x)*(1 - 12*x + 24*x^2 - 5*x^3)). - Colin Barker, Sep 12 2018
EXAMPLE
Some solutions for n=4:
..1..0..1..0..0....1..0..0..0..0....1..0..0..0..0....1..0..0..0..0
..1..0..1..0..1....0..0..0..0..0....1..0..1..0..0....1..0..0..0..0
..0..0..1..0..0....1..0..0..0..1....1..0..1..0..0....0..0..0..0..1
..1..0..0..1..0....0..1..0..0..1....1..0..1..0..0....1..0..0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 02 2013
STATUS
approved