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A221622 Number of nX7 arrays with each row a permutation of 1..7 having at least as many downsteps as the preceding row 1

%I

%S 5040,17052210,49096652080,130516916069715,332469512259607296,

%T 827196295133181978340,2031241364747667201263520,

%U 4951481629224145844957738085,12021159412525485182456506260880

%N Number of nX7 arrays with each row a permutation of 1..7 having at least as many downsteps as the preceding row

%C Column 7 of A221623

%H R. H. Hardin, <a href="/A221622/b221622.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5040*a(n-1) -8349390*a(n-2) +5234439280*a(n-3) -936232732785*a(n-4) +51206316902496*a(n-5) -99624831647040*a(n-6) +49349521382400*a(n-7)

%e Some solutions for n=3

%e ..1..4..2..3..5..6..7....1..4..2..3..5..6..7....1..4..2..3..5..6..7

%e ..2..1..3..7..6..4..5....2..1..3..5..4..6..7....2..1..3..6..7..5..4

%e ..3..6..5..7..2..1..4....2..1..3..5..7..4..6....6..2..5..4..3..7..1

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 21 2013

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Last modified May 26 06:56 EDT 2022. Contains 354074 sequences. (Running on oeis4.)