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A006762
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Number of fixed polyominoes with n cells.
(Formerly M3534)
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3
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0, 0, 4, 17, 61, 214, 758, 2723, 9908, 36444, 135266, 505859, 1903888, 7204872, 27394664, 104592935, 400795842
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| This sequence counts only polyominoes that are strictly 2-dimensional - it excludes those where all the squares are in a single line. Thus for n>1, a(n) = A001168(n) - 2. - Franklin T. Adams-Watters, Jul 29 2007
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REFERENCES
| W. F. Lunnon, Counting multidimensional polyominoes. Computer Journal 18 (1975), no. 4, pp. 366-367.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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CROSSREFS
| Cf. A001168. A column of A195739.
Sequence in context: A202974 A034331 A107278 * A202752 A191272 A122231
Adjacent sequences: A006759 A006760 A006761 * A006763 A006764 A006765
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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