%I #5 Mar 30 2013 04:53:18
%S 2,4,14,52,210,888,3886,17448
%N Sequence i_n arising in enumeration of arrays of directed blocks (see Quaintance reference for precise definition).
%D Jocelyn Quaintance, Combinatoric Enumeration of TwoDimensional Proper Arrays, Discrete Math., 307 (2007), 18441864.
%F See Quaintance reference for generating functions that produce A129872A129886.
%K nonn,more
%O 1,1
%A _N. J. A. Sloane_, May 26 2007
