On Optimal Binary One-Error-Correcting Codes of Lengths $2^m-4$ and $2^m-3$

Best and Brouwer [Discrete Math. 17 (1977), 235– 245] proved that triply-shortened and doubly-shortened binary Hamming codes (which have length 2m − 4 and 2m − 3, respectively) are optimal. Properties of such codes are here studied, determining among other things parameters of certain subcodes. A utilization of these properties makes a computeraided classification of the optimal binary one-error-correcting codes of lengths 12 and 13 possible; there are 237610 and 117823 such codes, respectively (with 27375 and 17513 inequivalent extensions). This completes the classification of optimal binary oneerror-correcting codes for all lengths up to 15. Some properties of the classified codes are further investigated. Finally, it is proved that for any m ≥ 4, there are optimal binary one-error-correcting codes of length 2m − 4 and 2m − 3 that cannot be lengthened to perfect codes of length 2m − 1.