OFFSET
1,2
COMMENTS
Row 2 of A220226.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + a(n-2) + 6*a(n-3) + a(n-4) + 3*a(n-5) - 4*a(n-6) - 2*a(n-7) - 4*a(n-8).
Empirical g.f.: x*(1 - x)*(1 + 2*x)^2*(1 + x^2)*(1 + x + x^2) / (1 - 2*x - x^2 - 6*x^3 - x^4 - 3*x^5 + 4*x^6 + 2*x^7 + 4*x^8). - Colin Barker, Jul 31 2018
EXAMPLE
Some solutions for n=3:
..1..1..0....1..1..1....1..0..0....1..0..1....0..1..0....0..1..1....1..1..1
..1..1..0....1..0..1....0..0..0....1..1..1....1..1..1....0..1..1....0..1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 08 2012
STATUS
approved