%I #5 Jan 25 2016 15:54:08
%S 1,1,20,1680,359582,156245130,120386806922,150097348110878,
%T 283411248751268531
%N Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, down, down, up.
%Y Cf. A014606.
%K nonn
%O 0,3
%A _R. H. Hardin_, May 10 2010