OFFSET
1,1
COMMENTS
Column 4 of A224625.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..40
FORMULA
Empirical: a(n) = 3*a(n-1) - 2*a(n-2) - 2*a(n-3) + 3*a(n-4) - 2*a(n-6) + 2*a(n-8) - a(n-9) for n>13.
Empirical g.f.: x*(32029 - 74006*x + 24439*x^2 + 57602*x^3 - 55716*x^4 - 15033*x^5 + 48721*x^6 + 14698*x^7 - 49772*x^8 + 16668*x^9 + 300*x^10 + 64*x^11 + 4*x^12) / ((1 - x)^3*(1 + x)*(1 - x + x^2)*(1 - x^2 - x^3)). - Colin Barker, Sep 02 2018
EXAMPLE
Some solutions for n=2:
..1..1..1..1..1..1..0..2....0..1..0..0..0..0..0..0....1..0..0..0..0..0..0..2
..0..0..0..0..0..0..0..0....0..1..0..0..0..0..0..2....1..0..0..0..0..0..0..2
..0..0..0..0..0..0..0..0....0..1..0..0..0..0..0..1....2..0..0..0..0..0..0..1
..0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..1....2..0..0..0..0..0..0..1
..0..0..0..0..0..0..0..0....0..1..0..0..0..0..0..1....2..0..0..0..0..0..0..1
..1..1..0..2..1..1..1..1....0..1..0..0..0..0..0..1....1..0..0..0..0..0..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 12 2013
STATUS
approved