A138927 Indices k such that A020502(k)=Phi[k](-3) is prime, where Phi is a cyclotomic polynomial.

3, 5, 6, 7, 12, 13, 14, 18, 23, 24, 26, 30, 35, 36, 40, 42, 43, 60, 65, 66, 72, 77, 108, 126, 132, 142, 206, 215, 236, 276, 281, 286, 290, 304, 322, 359, 364, 391, 464, 487, 510, 522, 528, 529, 535, 558, 574, 577, 672, 680, 713, 731, 760, 799, 828, 892, 984

Offset: 1

Author

M. F. Hasler, Apr 03 2008

Keywords

• nonn

Links

• Robert Price, Table of n, a(n) for n = 1..157
• Yves Gallot, Cyclotomic polynomials and prime numbers
• Index entries for cyclotomic polynomials, values at X

Crossrefs

Cf. A020502, A138920-A138940.

Programs

Mathematica

Select[ Range[3, 1000], PrimeQ[ Cyclotomic[#, -3]] &] (* Robert G. Wilson v, Mar 25 2012 *)

PARI

for( i=1,999, ispseudoprime( polcyclo(i,-3)) && print1( i","))