OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) - 2*a(n-2); a(n) = 25*2^(n-1) - 4.
Empirical g.f.: x*(21 - 17*x) / ((1 - x)*(1 - 2*x)). - Colin Barker, Nov 19 2018
EXAMPLE
Some solutions for n=4:
..0..0..1....1..0..0....0..0..1....1..1..0....0..1..0....0..0..0....0..0..0
..0..0..1....1..0..1....0..1..0....1..1..0....0..1..0....0..0..1....0..0..0
..0..1..0....1..0..1....1..0..1....1..1..0....1..0..1....0..1..0....0..0..0
..0..1..0....1..1..0....0..1..0....1..1..0....0..1..0....0..1..0....0..1..1
..0..1..0....1..1..1....0..1..0....1..1..1....1..0..1....0..1..0....0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 27 2014
STATUS
approved