OFFSET
1,2
COMMENTS
Column 2 of A183927.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = a(n-1)+2*a(n-3)-a(n-4)-a(n-5)-a(n-6)-a(n-7)+2*a(n-8)+a(n-10)-a(n-11).
Empirical g.f.: x*(1 + x + 2*x^2 - x^5 - x^6 + 2*x^7 + x^9 - x^10) / ((1 - x)^4*(1 + x)*(1 + x^2)*(1 + x + x^2)^2). - Colin Barker, Oct 21 2017
EXAMPLE
All solutions for n=4
.-1....0...-1...-2...-1...-2
.-1....0....0....0...-1....0
..0....0....0....1....1....0
..2....0....1....1....1....2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 08 2011
STATUS
approved