A221626 Number of 4Xn arrays with each row a permutation of 1..n having at least as many downsteps as the preceding row

1, 5, 453, 85035, 51149685, 57614883627, 130516916069715, 492362067027383802, 3063154239917651379537, 28932140956374841410316707, 405028623674958829496315433651, 8040080740216333451541433497055002

Offset

1,2

Comments

Row 4 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..3..2....1..2..3....2..3..1....2..1..3....1..2..3....2..3..1
..2..3..1....2..1..3....1..2..3....1..3..2....3..1..2....1..2..3....2..3..1
..2..3..1....2..3..1....3..1..2....2..1..3....3..1..2....1..3..2....3..1..2
..1..3..2....2..3..1....2..1..3....3..1..2....2..3..1....2..1..3....1..3..2

Crossrefs

Sequence in context: A055305 A300971 A300928 * A332145 A144509 A240700

Adjacent sequences: A221623 A221624 A221625 * A221627 A221628 A221629

Keyword

nonn

Author

R. H. Hardin Jan 21 2013

Status

approved