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A258430 Primes in A088580. 3
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 (list; graph; refs; listen; history; text; internal format)
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 * A045353 A038985 A109652

Adjacent sequences:  A258427 A258428 A258429 * A258431 A258432 A258433

KEYWORD

nonn

AUTHOR

Robert Price, May 29 2015

STATUS

approved

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Last modified November 15 08:37 EST 2019. Contains 329144 sequences. (Running on oeis4.)