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%I #4 Jan 21 2013 07:30:10
%S 1,6,1818,1130256,3451956516,21241004664348,332469512259607296,
%T 9510929074212911717760,521875340203828179569609700,
%U 47602100904962622927705491352020,7181861163349151796773697873026037828
%N Number of 5Xn arrays with each row a permutation of 1..n having at least as many downsteps as the preceding row
%C Row 5 of A221623
%H R. H. Hardin, <a href="/A221627/b221627.txt">Table of n, a(n) for n = 1..13</a>
%e Some solutions for n=3
%e ..1..3..2....1..3..2....2..3..1....3..1..2....2..1..3....1..3..2....3..1..2
%e ..1..3..2....1..3..2....1..3..2....2..3..1....2..1..3....3..1..2....2..1..3
%e ..2..1..3....2..1..3....1..3..2....3..1..2....2..1..3....2..1..3....3..1..2
%e ..2..1..3....1..3..2....2..3..1....2..1..3....3..2..1....1..3..2....2..3..1
%e ..2..3..1....2..3..1....1..3..2....1..3..2....3..2..1....3..2..1....3..1..2
%K nonn
%O 1,2
%A _R. H. Hardin_ Jan 21 2013