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A250183 Numbers n such that Phi(30,n) is prime, where Phi is the cyclotomic polynomial. 2
2, 6, 7, 8, 9, 16, 18, 20, 26, 29, 31, 32, 33, 40, 41, 47, 57, 76, 82, 87, 88, 93, 101, 109, 120, 121, 125, 133, 140, 144, 162, 163, 175, 178, 183, 186, 191, 196, 215, 216, 218, 227, 233, 242, 253, 266, 267, 273, 276, 278, 304, 312, 317, 319, 328, 336, 374, 380 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

MATHEMATICA

Select[Range[400], PrimeQ[Cyclotomic[30, #]] &] (* Vincenzo Librandi, Jan 17 2015 *)

PROG

(PARI) isok(n) = isprime(polcyclo(30, n)); \\ Michel Marcus, Jan 17 2015

CROSSREFS

Cf. A246392.

Sequence in context: A138168 A047279 A162917 * A260139 A118471 A167456

Adjacent sequences:  A250180 A250181 A250182 * A250184 A250185 A250186

KEYWORD

nonn

AUTHOR

R. J. Mathar, Jan 12 2015

STATUS

approved

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Last modified May 11 12:47 EDT 2021. Contains 343791 sequences. (Running on oeis4.)