A258430 Primes in A088580.

2, 5, 7, 13, 19, 13, 29, 19, 43, 37, 61, 43, 41, 31, 73, 61, 43, 97, 79, 73, 73, 73, 61, 97, 127, 97, 73, 97, 127, 109, 181, 113, 157, 103, 211, 193, 163, 109, 281, 241, 211, 181, 157, 313, 337, 241, 271, 139, 337, 193, 181, 223, 229, 151, 373, 193, 241, 379

Offset

1,1

Comments

These primes are neither sorted nor uniqued. They are listed in the order found in A088580.

Links

Robert Price, Table of n, a(n) for n = 1..2967

OEIS Wiki, Cyclotomic Polynomials at x=n, n! and sigma(n)

Formula

a(n) = A088580(A065512(n)). - Michel Marcus, Jun 04 2015

Maple

with(numtheory): A258430:=n->`if`(isprime(1+sigma(n)), 1+sigma(n), NULL): seq(A258430(n), n=1..300); # Wesley Ivan Hurt, Jul 09 2015

Mathematica

Select[Table[1 + DivisorSigma[1, n], {n, 10000}], PrimeQ]

Prog

(Magma) [a: n in [1..300] | IsPrime(a) where a is 1 + SumOfDivisors(n)]; // Vincenzo Librandi, May 30 2015
(PARI) select(x->isprime(x), vector(200, n, 1+sigma(n))) \\ Michel Marcus, Jun 04 2015

Crossrefs

Cf. A088580, A065512.

Sequence in context: A160676 A169690 A144300 * A333242 A045353 A038985

Adjacent sequences: A258427 A258428 A258429 * A258431 A258432 A258433

Keyword

nonn

Author

Robert Price, May 29 2015

Status

approved