

A323357


Number of binary selfdual codes of length 2n (up to permutation equivalence) that have a unique automorphism group size.


1



1, 1, 1, 2, 2, 3, 4, 7, 9, 16, 23, 42, 68, 94, 124, 159, 187, 212
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OFFSET

1,4


COMMENTS

Two codes are said to be permutation equivalent if permuting the columns of one code results in the other code.
If permuting the columns of a code results in the same identical code the permutation is called an automorphism.
The automorphisms of a code form a group called the automorphism group.
Some codes have automorphism groups that contain the same number of elements. There are situations, both trivial and otherwise, that codes of different lengths can have the same size automorphism groups.
Some codes have automorphism group sizes that are unique to the code. This sequence only compares automorphism group sizes for codes with the same length.


LINKS



EXAMPLE

There are a(18) = 212 binary selfdual codes (up to permutation equivalence) of length 2*18 = 36 that have a unique automorphism group size.


CROSSREFS



KEYWORD

nonn,more


AUTHOR



STATUS

approved



