A264656 Number of n X 1 arrays of permutations of 0..n*1-1 with rows nondecreasing modulo 2 and columns nondecreasing modulo 5.

1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 96, 288, 864, 2592, 7776, 31104, 124416, 497664, 1990656, 7962624, 39813120, 199065600, 995328000, 4976640000, 24883200000, 149299200000, 895795200000, 5374771200000, 32248627200000, 193491763200000, 1354442342400000

Offset: 1

Author

R. H. Hardin, Nov 20 2015

Keywords

• nonn

Comments

Column 1 of A264659.

Examples

			All solutions for n=8
..5....0....0....5....5....5....0....0
..0....5....5....0....0....0....5....5
..1....6....6....6....6....1....1....1
..6....1....1....1....1....6....6....6
..7....7....2....2....7....2....7....2
..2....2....7....7....2....7....2....7
..3....3....3....3....3....3....3....3
..4....4....4....4....4....4....4....4
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..74

Crossrefs

Cf. A264659.

Column k=5 of A275062.

Programs

Mathematica

Table[Product[Floor[(n + i)/5]!, {i, 0, 4}], {n, 1, 30}] (* Vaclav Kotesovec, Oct 02 2018 *)

Formula

a(n) = Product_{i=0..4} floor((n+i)/5)!. - Alois P. Heinz, Jul 12 2016

a(n) ~ (2*Pi*n)^2 * n! / 5^(n + 5/2). - Vaclav Kotesovec, Oct 02 2018