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

1,3

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

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).

LINKS

Table of n, a(n) for n=1..17.

CROSSREFS

Cf. A001168. A column of A195739.

Sequence in context: A202974 A034331 A107278 * A202752 A286210 A252815

Adjacent sequences:  A006759 A006760 A006761 * A006763 A006764 A006765

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified August 24 04:58 EDT 2017. Contains 291052 sequences.