%I A006748 M0366
%S A006748 0,0,1,0,2,2,7,5,26,22,91,79,326,301,1186,1117,4352,4212,16119,15849,60174,
%T A006748 60089,226146,228426,854803,872404,3247207,3342579
%N A006748 Number of diagonally symmetric polyominoes with n cells.
%C A006748 This sequence counts polyominoes with exactly the symmetry group of order 
               2 generated by a single reflection about a diagonal.
%D A006748 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A006748 D. H. Redelmeier, Counting polyominoes: yet another attack, Discrete 
               Math., 36 (1981), 191-203.
%H A006748 Tomas Oliveira e Silva, <a href="http://www.ieeta.pt/~tos/animals.html">
               Enumeration of polyominoes</a>
%H A006748 D. H. Redelmeier, <a href="a056877.png">Table 3</a> of Counting polyominoes...
%Y A006748 Cf. A000105, A001168, A006746, A056877, A006748, A056878, A006747.
%Y A006748 Sequences classifying polyominoes by symmetry group: A000105, A006746, 
               A006747, A006748, A006749, A056877, A056878, A142886, A144553, A144554.
%Y A006748 Sequence in context: A074144 A011146 A058625 this_sequence A131049 A126851 
               A142070
%Y A006748 Adjacent sequences: A006745 A006746 A006747 this_sequence A006749 A006750 
               A006751
%K A006748 nonn
%O A006748 1,5
%A A006748 N. J. A. Sloane (njas(AT)research.att.com).
%E A006748 Extended to n=28 by Tomas Oliveira e Silva.