OFFSET
1,1
COMMENTS
Column 3 of A206169.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 745*a(n-2) - 489*a(n-3) - 5808*a(n-4) + 1584*a(n-5) + 10368*a(n-6) for n>7.
Empirical g.f.: x*(641 + 13541*x - 27849*x^2 - 116389*x^3 + 121496*x^4 + 247632*x^5 - 70272*x^6) / ((1 - x - 4*x^2)*(1 - 741*x^2 - 252*x^3 + 2592*x^4)). - Colin Barker, Jun 13 2018
EXAMPLE
Some solutions for n=4:
..0..0..0..1....0..0..0..1....0..0..0..0....0..0..0..0....0..1..1..2
..0..1..0..0....0..1..0..0....0..1..0..1....0..0..0..0....1..1..0..1
..2..1..2..2....0..1..2..1....1..0..1..0....1..0..1..0....0..3..0..1
..2..2..2..3....3..0..1..0....1..0..1..3....1..3..3..2....2..0..1..1
..1..3..1..0....1..2..1..2....0..0..0..1....1..1..3..3....2..3..2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 04 2012
STATUS
approved