A138919 Indices k such that A020510(k)=Phi[k](-11) is prime, where Phi is a cyclotomic polynomial.

5, 7, 18, 20, 21, 30, 34, 36, 38, 52, 54, 60, 90, 104, 117, 123, 146, 159, 179, 182, 229, 278, 388, 405, 410, 439, 552, 557, 735, 806, 807, 1220, 1272, 1568, 1688, 1696, 1710, 1814, 2136, 2262, 2288, 2862, 3679, 3814, 4058, 4304, 4480, 5070, 5136, 5154

Offset

1,1

Comments

Larger values are probable primes.

Links

Robert Price, Table of n, a(n) for n = 1..91

Yves Gallot, Cyclotomic polynomials and prime numbers

Index entries for cyclotomic polynomials, values at X

Mathematica

Select[Range[1000], PrimeQ[Cyclotomic[#, -11]] &]

Prog

(PARI) for( i=1, 999, ispseudoprime( polcyclo(i, -11)) & print1(", ", i)) /* use ...subst(polcyclo(i), x, -11)... in PARI < 2.4.2 */

Crossrefs

Cf. A020510, A138920-A138940, A070518-A070527.

Sequence in context: A271656 A145582 A034762 * A345909 A214414 A153192

Adjacent sequences: A138916 A138917 A138918 * A138920 A138921 A138922

Keyword

nonn

Author

M. F. Hasler, Apr 04 2008

Extensions

Edited by T. D. Noe, Oct 30 2008

a(32)-a(44) from Robert Price, Mar 16 2012

a(45)-a(50) from Robert Price, Apr 14 2012

Status

approved