OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) - 15*a(n-2) + a(n-3) + 33*a(n-4) - 28*a(n-5) - 12*a(n-6) + 16*a(n-7) + a(n-8) - 2*a(n-9).
Empirical g.f.: x*(9 - 40*x + 33*x^2 + 68*x^3 - 99*x^4 - 13*x^5 + 51*x^6 + x^7 - 6*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:
..0....1....0....0....1...-1....0....1....1....0....1...-1....1....0....1...-1
.-1...-1....0....1....0....0....0...-1...-1...-1....1....0....0....1....0....0
..0....0...-1...-1...-1....1....1....0...-1....1....1....0....0....0....1...-1
.-1....0....0....0....0....0...-1....0...-1....1...-1....0....1...-1....0....1
..0....0...-1....1....0...-1...-1....0...-1....1....0....1....0....0....0....1
..0...-1....0...-1...-1....1...-1....0...-1....1...-1....0....1...-1....0...-1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 12 2012
STATUS
approved