OFFSET
1,1
COMMENTS
Column 4 of A205193.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) +a(n-2) -a(n-3) +a(n-4) for n>6.
Empirical g.f.: 8*x*(9 + 4*x - 2*x^2 + 8*x^3 - x^5) / (1 - x - x^2 + x^3 - x^4). - Colin Barker, Jun 11 2018
EXAMPLE
Some solutions for n=4:
..1..1..0..1..1....1..1..0..1..1....1..1..1..0..1....1..0..1..1..0
..1..1..1..0..1....1..1..1..0..1....1..1..0..1..1....0..1..1..1..0
..0..1..1..1..0....0..1..1..1..0....0..0..1..1..1....1..1..1..0..1
..1..0..1..1..1....1..0..1..1..0....0..0..1..1..0....1..1..0..1..1
..1..1..0..1..1....1..1..0..0..1....0..1..0..0..1....0..0..1..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 23 2012
STATUS
approved