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A010101 Maximal size of binary code of length n and asymmetric distance 2. 4
1, 2, 2, 4, 6, 12, 18, 36, 62 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Size of optimal single-error-correcting code for Z-channel.

REFERENCES

S. Butenko, P. Pardalos, I. Sergienko, V. P. Shylo and P. Stetsyuk, Estimating the size of correcting codes using extremal graph problems, Optimization, 227-243, Springer Optim. Appl., 32, Springer, New York, 2009.

T. Etzion, New lower bounds for asymmetric and unidirectional codes, IEEE Trans. Inform. Theory, 37 (1991), 1696-1705.

J. H. Weber, Bounds and Constructions for Binary Block Codes Correcting Asymmetric or Unidirectional Errors, Ph. D. Thesis, Tech. Univ. Delft, 1989.

J. H. Weber, C. de Vroedt and D. E. Boekee, Bounds and constructions for binary codes of length less than 24 and asymmetric distance less than 6, IEEE Trans. Inform. Theory, 34 (1988), 1321-1332.

LINKS

Table of n, a(n) for n=1..9.

Etzion, Tuvi and Ostergard, Patric R. J., Greedy and heuristic algorithms for codes and colorings, IEEE Transactions on Information Theory, 44 (1998), 382-388.

N. J. A. Sloane, Challenge Problems: Independent Sets in Graphs

CROSSREFS

Sequence in context: A267610 A291365 A154779 * A274942 A028408 A226452

Adjacent sequences:  A010098 A010099 A010100 * A010102 A010103 A010104

KEYWORD

nonn,nice,hard

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Next 3 terms are known to be in the range 112-117, 198-210 and 379-410 respectively.

STATUS

approved

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Last modified October 23 17:32 EDT 2019. Contains 328373 sequences. (Running on oeis4.)