A177617 - OEIS

%I #5 Mar 02 2016 11:01:03

%S 1,1,20,1680,369600,167510862,135702841152,178756061502340,

%T 357729925926146006

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

%Y Cf. A014606.

%K nonn

%O 0,3

%A _R. H. Hardin_, May 10 2010