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A258977 Primes in A258974. 3
2, 17, 37, 197, 577, 577, 401, 1297, 577, 1601, 3137, 2917, 3137, 8101, 7057, 15377, 2917, 14401, 14401, 8101, 7057, 15877, 5477, 15377, 15877, 7057, 50177, 14401, 32401, 8101, 14401, 24337, 44101, 78401, 12101, 57601, 44101, 32401, 50177, 24337, 30977 (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 A258974.

LINKS

Robert Price, Table of n, a(n) for n = 1..1786

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

FORMULA

a(n) = A258974(A258976(n)).

MAPLE

with(numtheory): A258977:=n->`if`(isprime(1+sigma(n)^2), 1+sigma(n)^2, NULL): seq(A258977(n), n=1..300); # Wesley Ivan Hurt, Jul 09 2015

MATHEMATICA

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

Select[Table[Cyclotomic[4, DivisorSigma[1, n]], {n, 10000}], PrimeQ]

PROG

(MAGMA) [m: n in [1..200] | IsPrime(m) where m is 1 + DivisorSigma(1, n)^2]; // Vincenzo Librandi, Jun 16 2015

(PARI) for(n=1, 100, p=1+sigma(n)^2; if(isprime(p), print1(p, ", "))) \\ Derek Orr, Jun 18 2015

CROSSREFS

Cf. A000203, A258974, A258976.

Sequence in context: A095075 A307161 A294560 * A069042 A121923 A212276

Adjacent sequences:  A258974 A258975 A258976 * A258978 A258979 A258980

KEYWORD

nonn

AUTHOR

Robert Price, Jun 15 2015

STATUS

approved

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Last modified May 14 13:45 EDT 2021. Contains 343884 sequences. (Running on oeis4.)