OFFSET
1,1
COMMENTS
Row 4 of A200154.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-1) - a(n-2) + 2*a(n-3) - 4*a(n-4) + 2*a(n-5) - a(n-6) + 2*a(n-7) - a(n-8).
Empirical g.f.: x*(4 + x + 8*x^2 - 2*x^3 + 4*x^4 + 2*x^6 - x^7) / ((1 - x)^4*(1 + x + x^2)^2). - Colin Barker, Mar 02 2018
EXAMPLE
Some solutions for n=6:
..3....4....2....0....0....4....4....3....3....3....2....2....6....3....5....3
..3....4....6....4....1....1....5....1....0....0....2....2....1....4....1....4
..4....3....6....6....3....0....4....1....0....1....3....2....1....4....0....3
..6....1....2....6....6....1....1....3....3....6....5....2....6....3....2....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 13 2011
STATUS
approved