OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..55
FORMULA
Empirical: a(n) = 5*a(n-1) - 3*a(n-2) - 17*a(n-3) + 17*a(n-4) + 22*a(n-5) - 18*a(n-6) - 14*a(n-7) + 3*a(n-8) + 2*a(n-9).
Empirical g.f.: x*(9 - 18*x - 31*x^2 + 48*x^3 + 45*x^4 - 27*x^5 - 23*x^6 + x^7 + 2*x^8) / ((1 + x)*(1 - 2*x)*(1 - x - x^2)*(1 - 2*x - x^2)*(1 - x - 2*x^2 + x^3)). - Colin Barker, Jul 18 2018
EXAMPLE
Some solutions for n=5:
.-1....0...-1....1...-1....0....0....1....0....0....0....1....0....0....1....1
.-1....0....1...-1....0....0....1....1....0....1...-1....1....0....1...-1....0
..1...-1....1...-1....1....1....1....1....0...-1....0....1....0...-1...-1....1
..0....0....1...-1....0...-1....1...-1....1...-1...-1....0....1....0....1...-1
..0....1....1...-1...-1....1....0...-1...-1....1....0...-1....1....0....1....1
..1....0...-1....1....0...-1....0...-1....1...-1...-1....0....1...-1...-1...-1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 14 2012
STATUS
approved