A248840 Number of length n arrays x(i), i=1..n with x(i) in 0..i and no value appearing more than 6 times.

2, 6, 24, 120, 720, 5040, 40318, 362804, 3626872, 39874764, 478139586, 6209677488, 86828161058, 1300490408860, 20771844841954, 352424863147204, 6329638315606052, 119970031702245396, 2393022889885984816

Offset: 1

Author

R. H. Hardin, Oct 15 2014

Keywords

• nonn

Comments

Column 6 of A248842

Examples

			Some solutions for n=6
..0....0....0....0....1....1....0....1....0....1....0....0....1....0....0....0
..1....1....1....1....1....0....0....0....2....0....1....1....1....2....0....1
..1....1....3....3....0....1....2....3....1....0....1....1....0....0....2....3
..0....2....2....1....2....0....2....1....0....4....2....1....2....3....3....4
..1....2....0....2....5....1....5....2....0....1....4....3....0....5....4....1
..2....0....6....3....2....0....1....4....4....2....6....4....3....5....4....3
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..109