A259186 Primes in A259184.

7, 13, 43, 31, 211, 157, 307, 757, 307, 1483, 1723, 3541, 1723, 5113, 3907, 8191, 3541, 8011, 1723, 6007, 5113, 5113, 14281, 5113, 14281, 8011, 3541, 28057, 20593, 20593, 5113, 37831, 28057, 17293, 14281, 8011, 12433, 28057, 20593, 14281, 24181, 10303, 46441

Offset: 1

Author

Robert Price, Jun 20 2015

Keywords

• easy
• nonn

Comments

These primes are neither sorted nor uniqued. They are listed in the order found in A259184.

Links

• Robert Price, Table of n, a(n) for n = 1..1737
• OEIS Wiki, Cyclotomic Polynomials at x=n, n! and sigma(n)

Crossrefs

Cf. A000203, A259184, A259185.

Programs

Maple

with(numtheory): A259186:=n->`if`(isprime(1 - sigma(n) + sigma(n)^2), 1 - sigma(n) + sigma(n)^2, NULL): seq(A259186(n), n=1..200); # Wesley Ivan Hurt, Jul 09 2015

Mathematica

Select[Table[1 - DivisorSigma[1, n] + DivisorSigma[1, n]^2, {n, 10000}], PrimeQ]
Select[Table[Cyclotomic[6, DivisorSigma[1, n]], {n, 10000}], PrimeQ]

Formula

a(n) = A259184(A259185(n)).