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

Author

R. H. Hardin Jan 21 2013

Keywords

• nonn

Comments

Row 4 of A221623

Examples

			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
		

Links

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