%I #6 Nov 02 2013 17:32:44

%S 1,15,767,93621,22431655,9362799454,6260161965339,6298506200484865,

%T 9087853319185940117,18101094912700638755191

%N Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, up.

%K nonn

%O 1,2

%A _R. H. Hardin_, May 10 2010

%E a(9)-a(10) from _Alois P. Heinz_, Nov 02 2013