A028312 Odd numbers k such that {1..k-1} cannot be partitioned into disjoint sets I, J such that 2I == -J (mod k) and I, J are unions of cyclotomic cosets mod k.

3, 9, 11, 15, 19, 21, 27, 33, 39, 43, 45, 51, 55, 57, 59

Offset

1,1

Links

Table of n, a(n) for n=1..15.

F. J. MacWilliams, A. M. Odlyzko, N. J. A. Sloane and H. N. Ward, Self-Dual Codes over GF(4), J. Combin. Theory, A 25 288-318 1978.

Crossrefs

Cf. A028311.

Sequence in context: A190226 A059326 A370873 * A310315 A074486 A131861

Adjacent sequences: A028309 A028310 A028311 * A028313 A028314 A028315

Keyword

nonn,more

Author

N. J. A. Sloane

Extensions

a(10)-a(15) from Sean A. Irvine, Jan 11 2020

Status

approved