A028311 Odd numbers k such that {1..k-1} can be partitioned into disjoint sets I, J with 2I == -J (mod k) such that I, J are unions of cyclotomic cosets mod k.

5, 7, 13, 17, 23, 25, 29, 31, 35, 37, 41, 47, 49, 53, 61

Offset

1,1

Links

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

Sean A. Irvine, Java program (github)

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. A028312.

Sequence in context: A342705 A314321 A314322 * A335075 A240716 A216773

Adjacent sequences: A028308 A028309 A028310 * A028312 A028313 A028314

Keyword

nonn,more

Author

N. J. A. Sloane

Extensions

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

Status

approved