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Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, down, down.
0

%I #6 Nov 02 2013 16:39:42

%S 1,70,25446,29416791,83400344760,492319974701196,5405431813676888595,

%T 101632942861784833336188

%N Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, down, down.

%K nonn

%O 1,2

%A _R. H. Hardin_, May 10 2010

%E a(8) from _Alois P. Heinz_, Nov 02 2013