

A322299


Number of distinct automorphism group sizes for binary selfdual codes of length 2n.


5



1, 1, 1, 2, 2, 3, 4, 7, 9, 16, 24, 48, 85, 149, 245, 388
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OFFSET

1,4


COMMENTS

Codes are vector spaces with a metric defined on them. Specifically, the metric is the hamming distance between two vectors. Vectors of a code are called codewords.
A code is usually represented by a generating matrix. The row space of the generating matrix is the code itself.
Selfdual codes are codes such all codewords are pairwise orthogonal to each other.
Two codes are called permutation equivalent if one code can be obtained by permuting the coordinates (columns) of the other code.
The automorphism group of a code is the set of permutations of the coordinates (columns) that result in the same identical code.


LINKS



EXAMPLE

There are a(16) = 388 distinct sizes for the automorphism groups of the binary selfdual codes of length 16. In general, two automorphism groups with the same size are not necessarily isomorphic.


CROSSREFS



KEYWORD

nonn,more


AUTHOR



STATUS

approved



