%I A000104 M1424 N0560
%S A000104 1,1,1,2,5,12,35,107,363,1248,4460,16094,58937,217117,805475,
%T A000104 3001127,11230003,42161529,158781106,599563893,2269506062,
%U A000104 8609442688,32725637373,124621833354,475368834568,1816103345752,6948228104703
%N A000104 Number of n-celled polyominoes without holes.
%D A000104 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A000104 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A000104 E. V. Konstantinova and M. V. Vidyuk, Discriminating tests of information 
               and toplogical indices; animals and trees; J. Chem. Inf. Comput. 
               Sci., 43 (2003), 1860-1871.
%D A000104 J. S. Madachy, Pentominoes - Some Solved and Unsolved Problems, J. Rec. 
               Math., 2 (1969), 181-188.
%D A000104 T. R. Parkin, L. J. Lander and D. R. Parkin, ``Polyomino enumeration 
               results,'' SIAM Fall Meeting, Santa Barbara, California, 1967.
%D A000104 R. C. Read, Contributions to the cell growth problem, Canad. J. Math., 
               14 (1962), 1-20.
%H A000104 Tomas Oliveira e Silva, <a href="http://www.ieeta.pt/~tos/animals.html">
               Enumeration of polyominoes</a>
%Y A000104 Cf. A000105, A006746, A056877, A006748, A056878, A006747, A006749, A006884, 
               A006885, A006877, A006878, A033492, A054361.
%Y A000104 Sequence in context: A054359 A148287 A036357 this_sequence A000105 A055192 
               A108555
%Y A000104 Adjacent sequences: A000101 A000102 A000103 this_sequence A000105 A000106 
               A000107
%K A000104 nonn,nice,hard
%O A000104 0,4
%A A000104 N. J. A. Sloane (njas(AT)research.att.com).
%E A000104 Extended to n=26 by Tomas Oliveira e Silva.