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A006749 Number of asymmetric polyominoes with n cells.
(Formerly M3906)
13
0, 0, 0, 1, 5, 20, 84, 316, 1196, 4461, 16750, 62878, 237394, 899265, 3422111, 13069026, 50091095, 192583152, 742560511, 2870523142, 11122817672, 43191285751, 168046076423, 654997492842, 2557223459805, 9999080270766, 39152997087077, 153511067364760 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

This sequence counts polyominoes whose symmetry group has order 1.

REFERENCES

A. R. Conway and A. J. Guttmann, On two-dimensional percolation, J. Phys. A: Math. Gen. 28(1995) 891-904.

D. H. Redelmeier, Counting polyominoes: yet another attack, Discrete Math., 36 (1981), 191-203.

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..28.

Tomas Oliveira e Silva, Enumeration of polyominoes

D. H. Redelmeier, Table 3 of Counting polyominoes...

CROSSREFS

Cf. A000105, A001168, A006746, A056877, A006748, A056878, A006747, A006749, A006884, A006885, A006877, A006878, A033492.

Sequences classifying polyominoes by symmetry group: A000105, A006746, A006747, A006748, A006749, A056877, A056878, A142886, A144553, A144554.

Sequence in context: A030520 A183933 A056884 * A002213 A099949 A006231

Adjacent sequences:  A006746 A006747 A006748 * A006750 A006751 A006752

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Extended to n=28 by Tomas Oliveira e Silva.

STATUS

approved

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Last modified September 20 23:09 EDT 2014. Contains 247020 sequences.