A160497 Values of pq such that there are only two residue classes (mod pq) of primes r that produce flat cyclotomic polynomial Phi(pqr,x).

15, 35, 65, 77, 85, 91, 95, 115, 119, 133, 143, 161, 185, 187, 209, 215, 217, 221, 235, 247, 259, 265, 287, 299, 319, 323, 329, 335, 341, 365, 371, 377, 391, 403, 407, 413, 415, 427, 437, 451, 469, 473, 481, 485, 493, 511, 515, 517, 527

Offset: 1

Author

T. D. Noe, May 15 2009

Keywords

• nonn

Comments

Except for 91, 95, 287, and 473, it appears that for prime p>3, pq is here only if q-1 and q+1 are not multiples of p.

Crossrefs

A160496