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A264557
Number of n X 1 arrays of permutations of 0..n*1-1 with rows nondecreasing modulo 2 and columns nondecreasing modulo 3.
9
1, 1, 1, 2, 4, 8, 24, 72, 216, 864, 3456, 13824, 69120, 345600, 1728000, 10368000, 62208000, 373248000, 2612736000, 18289152000, 128024064000, 1024192512000, 8193540096000, 65548320768000, 589934886912000, 5309413982208000, 47784725839872000
OFFSET
1,4
COMMENTS
Column 1 of A264560.
LINKS
FORMULA
a(n) = Product_{i=0..2} ceiling((n-i)/3)!. - Alois P. Heinz, Jul 09 2016
a(n) ~ 2 * Pi * (n+1)! / 3^(n + 3/2). - Vaclav Kotesovec, Oct 02 2018
EXAMPLE
All solutions for n=4
..0....3
..3....0
..1....1
..2....2
MATHEMATICA
Table[Product[Floor[(n + i)/3]!, {i, 0, 2}], {n, 1, 30}] (* Vaclav Kotesovec, Oct 02 2018 *)
CROSSREFS
Cf. A264560.
Column k=3 of A275062.
Sequence in context: A264570 A115115 A026097 * A067646 A152875 A179190
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 17 2015
STATUS
approved