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A006762 Number of fixed polyominoes with n cells.
(Formerly M3534)
+0
2
0, 0, 4, 17, 61, 214, 758, 2723, 9908, 36444, 135266, 505859, 1903888, 7204872, 27394664, 104592935, 400795842 (list; graph; listen)
OFFSET

1,3

COMMENT

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

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

W. F. Lunnon, Counting multidimensional polyominoes. Computer Journal 18 (1975), no. 4, pp. 366-367.

CROSSREFS

Cf. A001168.

Sequence in context: A027075 A034331 A107278 this_sequence A122231 A119916 A005784

Adjacent sequences: A006759 A006760 A006761 this_sequence A006763 A006764 A006765

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

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Last modified November 27 14:50 EST 2009. Contains 167570 sequences.


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