%I #4 Oct 15 2014 14:45:34
%S 2,6,24,120,720,5038,40260,361636,3606044,39517182,472002456,
%T 6102356222,84896359836,1264499036118,20075760897736,338430468325576,
%U 6037037185793372,113608224705704476,2249252806749536964
%N Number of length n arrays x(i), i=1..n with x(i) in 0..i and no value appearing more than 5 times
%C Column 5 of A248842
%H R. H. Hardin, <a href="/A248839/b248839.txt">Table of n, a(n) for n = 1..136</a>
%e Some solutions for n=6
%e ..1....1....0....1....0....1....1....1....0....0....0....1....1....0....0....1
%e ..2....2....2....2....2....1....1....0....2....1....2....2....1....2....2....0
%e ..3....3....0....2....1....3....0....1....0....0....1....0....2....3....0....0
%e ..2....1....2....1....0....4....0....3....0....2....1....1....3....2....1....4
%e ..1....4....4....5....1....2....2....2....5....0....4....4....5....2....0....3
%e ..0....0....2....2....5....3....4....0....5....4....1....4....0....0....5....6
%K nonn
%O 1,1
%A _R. H. Hardin_, Oct 15 2014
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