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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 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 February 2 21:10 EST 2023. Contains 360024 sequences. (Running on oeis4.)