OFFSET
1,1
COMMENTS
Row 3 of A207928.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 2*a(n-3) + a(n-4) for n>5.
Empirical g.f.: 6*x*(1 + 4*x - 2*x^3 - x^4) / ((1 + x^2)*(1 - 2*x - x^2)). - Colin Barker, Jun 26 2018
EXAMPLE
Some solutions for n=10:
..1..1..0..1..1..1..0..1..1..0....1..0..1..1..0..1..1..1..1..1
..0..0..1..1..0..0..1..1..0..0....1..0..0..1..1..0..1..1..0..0
..0..1..1..0..1..1..1..0..0..1....0..1..1..0..1..1..0..0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 21 2012
STATUS
approved