A138937 Indices k such that A019325(k)=Phi[k](7) is prime, where Phi is a cyclotomic polynomial.

5, 6, 13, 18, 21, 28, 30, 34, 36, 46, 48, 50, 54, 55, 58, 63, 76, 84, 94, 105, 122, 131, 148, 149, 224, 280, 288, 296, 332, 352, 456, 528, 531, 581, 650, 654, 730, 740, 759, 1026, 1047, 1065, 1460, 1660, 1699, 1959, 2067, 2260, 2380, 2665, 2890, 3238, 4020

Offset

1,1

Links

Robert Price, Table of n, a(n) for n = 1..95

Yves Gallot, Cyclotomic polynomials and prime numbers

Index entries for cyclotomic polynomials, values at X

Mathematica

Select[Range[1000], PrimeQ[Cyclotomic[#, 7]] &]

Prog

(PARI) for( i=1, 999, ispseudoprime( polcyclo(i, 7)) && print1( i", ")) /* use ...subst(polcyclo(i), x, 7)... in PARI < 2.4.2 */

Crossrefs

Cf. A019325, A138920-A138940.

Sequence in context: A303139 A322611 A030356 * A314291 A314292 A294572

Adjacent sequences: A138934 A138935 A138936 * A138938 A138939 A138940

Keyword

nonn

Author

M. F. Hasler, Apr 03 2008

Extensions

a(40)-a(53) from Robert Price, Apr 18 2012

Status

approved