OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n=1..57
FORMULA
Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3) + a(n-4) - 2*a(n-5) + a(n-6) for n>=10.
Empirical g.f.: x*(3 - x - x^2 + x^4 + 5*x^6 - x^7 - 2*x^8) / ((1 - x)^2*(1 - 2*x - x^4)). - Colin Barker, Feb 22 2018
EXAMPLE
All solutions for n=2:
...0.0.1...0.1.1...0.0.1...0.1.1...1.1.1...0.0.1...1.1.1...0.1.0...1.1.0
...0.0.1...0.0.1...0.1.1...0.1.1...0.0.1...1.1.1...1.0.1...0.1.1...0.1.1
------
...1.0.0...1.0.1
...1.1.1...1.1.1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 03 2009
STATUS
approved