%I A006749 M3906
%S A006749 0,0,0,1,5,20,84,316,1196,4461,16750,62878,237394,899265,3422111,13069026,
%T A006749 50091095,192583152,742560511,2870523142,11122817672,43191285751,
%U A006749 168046076423,654997492842,2557223459805,9999080270766,39152997087077,
               153511067364760
%N A006749 Number of asymmetric polyominoes with n cells.
%C A006749 This sequence counts polyominoes whose symmetry group has order 1.
%D A006749 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A006749 A. R. Conway and A. J. Guttmann, On two-dimensional percolation, J. Phys. 
               A: Math. Gen. 28(1995) 891-904.
%D A006749 D. H. Redelmeier, Counting polyominoes: yet another attack, Discrete 
               Math., 36 (1981), 191-203.
%H A006749 Tomas Oliveira e Silva, <a href="http://www.ieeta.pt/~tos/animals.html">
               Enumeration of polyominoes</a>
%H A006749 D. H. Redelmeier, <a href="a056877.png">Table 3</a> of Counting polyominoes...
%Y A006749 Cf. A000105, A001168, A006746, A056877, A006748, A056878, A006747, A006749, 
               A006884, A006885, A006877, A006878, A033492.
%Y A006749 Sequences classifying polyominoes by symmetry group: A000105, A006746, 
               A006747, A006748, A006749, A056877, A056878, A142886, A144553, A144554.
%Y A006749 Sequence in context: A165203 A030520 A056884 this_sequence A002213 A099949 
               A006231
%Y A006749 Adjacent sequences: A006746 A006747 A006748 this_sequence A006750 A006751 
               A006752
%K A006749 nonn,nice
%O A006749 1,5
%A A006749 N. J. A. Sloane (njas(AT)research.att.com).
%E A006749 Extended to n=28 by Tomas Oliveira e Silva.