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A138938 Indices k such that A019326(k)=Phi[k](8) is prime, where Phi is a cyclotomic polynomial. 2
1, 3, 9, 30, 42, 78, 87, 138, 189, 303, 318, 330, 408, 462, 504, 561, 1002, 1389, 1746, 1794, 2040, 2418, 2790, 3894, 4077, 4722, 6738, 10641, 14610, 14616, 15294, 16662, 18966, 19059, 26142, 27144, 28299, 31638, 33639, 39360 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..40.

Yves Gallot, Cyclotomic polynomials and prime numbers

Index entries for cyclotomic polynomials, values at X

MATHEMATICA

Select[Range[1000], PrimeQ[Cyclotomic[#, 8]] &]

PROG

(PARI) for( i=1, 999, ispseudoprime( polcyclo(i, 8)) && print1( i", ")) /* use ...subst( polcyclo(i), x, 8)... in PARI < 2.4.2 */

CROSSREFS

Cf. A019326, A138920-A138940.

Sequence in context: A007472 A292756 A151451 * A154147 A179545 A163129

Adjacent sequences:  A138935 A138936 A138937 * A138939 A138940 A138941

KEYWORD

nonn

AUTHOR

M. F. Hasler, Apr 03 2008

EXTENSIONS

a(17)-a(40) from Robert Price, Apr 20 2012

STATUS

approved

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Last modified April 1 14:52 EDT 2020. Contains 333163 sequences. (Running on oeis4.)