OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..117
FORMULA
Empirical: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) + a(n-5) + a(n-6) + a(n-7).
Empirical g.f.: 2*x*(14 + 21*x + 25*x^2 + 26*x^3 + 24*x^4 + 19*x^5 + 11*x^6) / (1 - x - x^2 - x^3 - x^4 - x^5 - x^6 - x^7). - Colin Barker, Nov 01 2018
EXAMPLE
Some solutions for n=5:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....1....1....1....1....1....1....1....1....1....1....0....1....1
..2....2....2....2....2....2....2....2....2....2....2....2....2....1....2....2
..3....3....0....3....3....3....0....3....3....3....3....3....3....2....3....3
..4....4....3....4....4....0....3....4....4....4....4....4....1....3....4....4
..0....1....4....5....0....4....4....5....0....5....5....5....4....4....5....5
..5....5....5....1....5....5....5....6....5....6....0....3....5....5....6....1
..6....6....6....6....6....6....6....0....6....0....6....6....6....6....1....6
..1....0....1....0....1....1....1....3....2....5....1....0....0....1....0....0
..3....2....0....3....2....2....0....1....1....1....2....1....5....0....2....2
..2....3....2....2....3....3....2....2....3....2....3....2....2....2....3....3
..3....4....4....3....0....1....5....6....5....3....5....3....3....1....4....6
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 08 2014
STATUS
approved