%I M1969 #9 Mar 30 2012 16:44:53
%S 0,0,1,2,10,45,210,1002,4883,23797,116518,571471
%N Number of restricted hexagonal polyominoes with n cells.
%D A. T. Balaban, Enumeration of Cyclic Graphs, pp. 63-105 of A. T. Balaban, ed., Chemical Applications of Graph Theory, Ac. Press, 1976; see p. 75.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%Y Equals A000228 - A002216.
%Y Cf. A036359, A002216, A005963, A000228, A001998.
%K nonn
%O 1,4
%A _N. J. A. Sloane_.