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A258430 Primes in A088580. 3

%I

%S 2,5,7,13,19,13,29,19,43,37,61,43,41,31,73,61,43,97,79,73,73,73,61,97,

%T 127,97,73,97,127,109,181,113,157,103,211,193,163,109,281,241,211,181,

%U 157,313,337,241,271,139,337,193,181,223,229,151,373,193,241,379

%N Primes in A088580.

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

%H Robert Price, <a href="/A258430/b258430.txt">Table of n, a(n) for n = 1..2967</a>

%H OEIS Wiki, <a href="https://oeis.org/wiki/Cyclotomic Polynomials at x=n, n! and sigma(n)">Cyclotomic Polynomials at x=n, n! and sigma(n)</a>

%F a(n) = A088580(A065512(n)). - _Michel Marcus_, Jun 04 2015

%p 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

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

%o (MAGMA) [a: n in [1..300] | IsPrime(a) where a is 1 + SumOfDivisors(n)]; // _Vincenzo Librandi_, May 30 2015

%o (PARI) select(x->isprime(x), vector(200, n, 1+sigma(n))) \\ _Michel Marcus_, Jun 04 2015

%Y Cf. A088580, A065512.

%K nonn

%O 1,1

%A _Robert Price_, May 29 2015

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Last modified June 22 21:29 EDT 2021. Contains 345393 sequences. (Running on oeis4.)