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Search: id:A144554
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| A144554 |
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Number of polyominoes with n cells whose symmetry group (excluding reflections) has order at least 2. |
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+0
10
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| 1, 1, 1, 3, 3, 7, 8, 25, 25, 82, 85, 302, 307, 1111, 1131, 4216, 4267, 16076, 16253, 61976, 62475, 239927, 241447, 933576, 937574, 3644073, 3653624
(list; graph; listen)
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OFFSET
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1,4
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REFERENCES
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D. H. Redelmeier, Counting polyominoes: yet another attack, Discrete Math., 36 (1981), 191-203.
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LINKS
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Tomas Oliveira e Silva, Enumeration of polyominoes
D. H. Redelmeier, Table 3 of Counting polyominoes...
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FORMULA
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This is the sum of A142886, A056877, A144553, A056878 and A006747. - Joseph Myers, Dec 31 2008.
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CROSSREFS
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Sequences classifying polyominoes by symmetry group: A000105, A006746, A006747, A006748, A006749, A056877, A056878, A142886, A144553, A144554.
Adjacent sequences: A144551 A144552 A144553 this_sequence A144555 A144556 A144557
Sequence in context: A108046 A116157 A056357 this_sequence A143088 A131036 A034411
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KEYWORD
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nonn,more
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AUTHOR
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Frederick Schneider (frederick.william.schneider(AT)gmail.com), Dec 28 2008
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EXTENSIONS
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Edited by N. J. A. Sloane (njas(AT)research.att.com), Jan 01 2009
17 additional terms (just summing the terms from the 5 sequences specified in the description) Fred Schneider (frederick.william.schneider(AT)gmail.com), Jan 03 2009
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