A221628 Number of 6Xn arrays with each row a permutation of 1..n having at least as many downsteps as the preceding row

1, 7, 7279, 14576404, 230141263315, 7575106427737240, 827196295133181978340, 177037611175595181692394660, 86030164534670200470739520304375, 75149351745335662460465241596540458600

Offset

1,2

Comments

Row 6 of A221623

Links

R. H. Hardin, Table of n, a(n) for n = 1..13

Example

Some solutions for n=3
..2..3..1....1..2..3....1..3..2....1..3..2....3..1..2....1..3..2....3..1..2
..1..3..2....1..2..3....2..1..3....1..3..2....3..1..2....2..3..1....1..3..2
..3..1..2....2..1..3....2..3..1....2..3..1....1..3..2....2..1..3....2..1..3
..1..3..2....2..3..1....2..1..3....2..3..1....1..3..2....3..1..2....2..1..3
..2..3..1....3..1..2....1..3..2....3..1..2....2..1..3....2..3..1....2..1..3
..3..1..2....2..3..1....2..3..1....2..3..1....2..3..1....1..3..2....3..2..1

Crossrefs

Sequence in context: A343145 A068575 A158400 * A220879 A119528 A116266

Adjacent sequences: A221625 A221626 A221627 * A221629 A221630 A221631

Keyword

nonn

Author

R. H. Hardin Jan 21 2013

Status

approved