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
FORMULA
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
KEYWORD
nonn
AUTHOR
Robert Price, May 29 2015
STATUS
approved