cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A003179 Number of self-dual binary codes of length 2n (up to column permutation equivalence).

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 3, 4, 7, 9, 16, 25, 55, 103, 261, 731, 3295, 24147, 519492
Offset: 0

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Author

Keywords

Comments

The length 36 binary self dual codes have been classified. - Nathan J. Russell, Feb 14 2016
This is number of binary self-dual codes of length 2n up to column permutation equivalence. Sequence A028362 gives an actual count of all possible binary self-dual codes of length 2n. - Nathan J. Russell, Nov 25 2018

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Extensions

a(18) from Nathan J. Russell, Feb 14 2016
Name clarified by Nathan J. Russell, Nov 26 2018

A106163 Total number of (indecomposable or decomposable) Type II binary self-dual codes of length 8n.

Original entry on oeis.org

1, 1, 2, 9, 85, 94343
Offset: 0

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Author

N. J. A. Sloane, May 09 2005

Keywords

Comments

"There are 94343 inequivalent doubly even self-dual codes of length 40, 16470 of which are extremal" [Betsumiya et al.] - Jonathan Vos Post, Aug 06 2012

Crossrefs

A105685 Number of inequivalent codes attaining highest minimal distance of any Type I (strictly) singly-even binary self-dual code of length 2n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 1, 2, 7, 1, 1, 1, 3, 13, 3
Offset: 1

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Author

N. J. A. Sloane, May 06 2005, Aug 23 2008

Keywords

Examples

			At length 8 the only strictly Type I self-dual code is {00,11}^4, so a(4) = 1.
		

References

  • J. H. Conway and V. S. Pless, On the enumeration of self-dual codes, J. Comb. Theory, A28 (1980), 26-53.
  • F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier/North Holland, 1977.
  • V. S. Pless, The children of the (32,16) doubly even codes, IEEE Trans. Inform. Theory, 24 (1978), 738-746.

Crossrefs

A105674 gives the minimal distance of these codes, A106165 the number of codes of any minimal distance and A003179 the number of inequivalent codes allowing Type I or Type II and any minimal distance.
Showing 1-3 of 3 results.