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%I #5 Mar 31 2012 12:36:20
%S 1,20,436,9993,238856,5904049,149981369,3897334810,103211369665,
%T 2777315286064,75757347740370,2090701163682622,58284103429506565,
%U 1639251621061033507,46464491673819086074,1326158666350163625126
%N Number of permutations of n copies of 1..5 introduced in order 1..5 with no element equal to another within a distance of 3
%H R. H. Hardin, <a href="/A190922/b190922.txt">Table of n, a(n) for n = 1..61</a>
%e Some solutions for n=2
%e ..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....1
%e ..2....2....2....2....2....2....2....2....2....2....2....2....2....2....2....2
%e ..3....3....3....3....3....3....3....3....3....3....3....3....3....3....3....3
%e ..4....4....4....4....4....4....4....4....4....4....4....4....4....4....4....4
%e ..5....1....5....1....5....5....5....5....5....5....5....5....5....1....5....5
%e ..1....5....1....5....2....1....1....1....1....1....2....2....2....5....2....2
%e ..2....2....2....3....3....2....3....3....3....2....3....1....3....2....1....1
%e ..3....4....3....4....1....4....4....2....4....4....1....3....4....3....4....4
%e ..5....3....4....2....4....5....5....4....2....3....5....4....5....4....5....3
%e ..4....5....5....5....5....3....2....5....5....5....4....5....1....5....3....5
%K nonn
%O 1,2
%A _R. H. Hardin_ May 23 2011