OFFSET
1,1
COMMENTS
Column 1 of A202124.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) -a(n-2) +a(n-3) -a(n-4) for n>8.
Empirical g.f.: x*(3 + x + 2*x^2 - 3*x^3 - 2*x^4 - 6*x^5 - 2*x^6 - 2*x^7) / ((1 - x)*(1 - x - x^3)). - Colin Barker, May 27 2018
EXAMPLE
Some solutions for n=7:
..1....1....1....0....1....1....0....0....1....1...-1...-1...-1....1...-1....0
..1....0....1...-1....0....1...-1....1....1....1....0...-1...-1....0....0....0
..1...-1....1...-1....0....0...-1....1....1....1....0...-1....0....0....1....0
..1...-1....1....0....0...-1...-1....1....1....0....0...-1....1....0....1....0
..1....0....1....1....0...-1...-1....0....0...-1....0...-1....1....0....1....0
..1....1....1....1....0....0....0...-1...-1...-1....0...-1....0....0....1....0
..0....1....1....0...-1....1....1...-1...-1...-1....1...-1...-1....0....0....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 11 2011
STATUS
approved