OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n=1..49
FORMULA
Empirical: a(n) = 7*a(n-1) - 19*a(n-2) + 24*a(n-3) - 10*a(n-4) - 10*a(n-5) + 16*a(n-6) - 8*a(n-7) - a(n-8) + 3*a(n-9) - a(n-10) for n>=12.
Empirical g.f.: x*(1 + 3*x - 3*x^2 - 7*x^3 + 4*x^4 + x^6 - x^7 - 5*x^8 + x^9 + 2*x^10) / ((1 - x)^4*(1 - x - x^2)*(1 - 2*x - x^4)). - Colin Barker, Mar 25 2018
EXAMPLE
All solutions for n=2:
...1.1.1...1.1.1...1.1.1...1.1.1...0.0.0...0.0.1...1.0.0...1.0.1...1.1.0
...0.0.0...0.0.1...1.0.0...1.0.1...1.1.1...1.1.1...1.1.1...1.1.1...0.1.1
------
...0.1.1
...1.1.0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 03 2009
STATUS
approved