

A144554


Number of polyominoes with n cells whose symmetry group (excluding reflections) has order at least 2.


10



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;
refs;
listen;
history;
text;
internal format)



OFFSET

1,4


REFERENCES

D. H. Redelmeier, Counting polyominoes: yet another attack, Discrete Math., 36 (1981), 191203.


LINKS

Table of n, a(n) for n=1..27.
Tomás Oliveira e Silva, Enumeration of polyominoes
D. H. Redelmeier, Table 3 of Counting polyominoes...


FORMULA

This is the sum of A142886, A056877, A144553, A056878 and A006747.  Joseph Myers, Dec 31 2008.


CROSSREFS

Sequences classifying polyominoes by symmetry group: A000105, A006746, A006747, A006748, A006749, A056877, A056878, A142886, A144553, A144554.
Sequence in context: A056357 A288728 A213942 * A177936 A143088 A131036
Adjacent sequences: A144551 A144552 A144553 * A144555 A144556 A144557


KEYWORD

nonn,more


AUTHOR

Fred Schneider, Dec 28 2008


EXTENSIONS

Edited by N. J. A. Sloane, Jan 01 2009
17 additional terms (just summing the terms from the 5 sequences specified in the description) Fred Schneider, Jan 03 2009


STATUS

approved



