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) + 2*a(n-3); a(n) = 25*2^(n-1) + 2*n + 8.
Empirical g.f.: x*(35 - 78*x + 41*x^2) / ((1 - x)^2*(1 - 2*x)). - Colin Barker, Nov 18 2018
EXAMPLE
Some solutions for n=4:
..0..1..0..1....0..0..0..0....0..0..0..0....1..1..1..0....0..0..0..0
..0..1..0..1....0..1..1..1....0..0..0..0....1..1..1..0....0..0..0..0
..0..1..0..1....0..1..1..1....1..1..1..1....1..1..1..0....0..0..0..0
..0..1..0..1....0..1..1..1....0..0..0..0....1..1..1..1....0..0..0..1
..0..1..0..1....0..1..1..1....0..0..0..0....1..1..1..1....0..0..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 27 2014
STATUS
approved