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A259411
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Numbers n such that 1 - sigma(n) + sigma(n)^2 - sigma(n)^3 + sigma(n)^4 is prime.
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3
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2, 6, 11, 19, 33, 35, 37, 47, 57, 68, 79, 81, 82, 88, 118, 121, 129, 145, 157, 162, 179, 217, 226, 241, 245, 257, 258, 260, 262, 289, 306, 332, 378, 393, 430, 434, 441, 461, 465, 466, 473, 474, 477, 483, 485, 490, 499, 504, 509, 512, 518, 526, 528, 533, 550
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OFFSET
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1,1
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LINKS
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Robert Price, Table of n, a(n) for n = 1..1017
OEIS Wiki, Cyclotomic Polynomials at x=n, n! and sigma(n)
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MAPLE
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with(numtheory): A259411:=n->`if`(isprime(1-sigma(n)+sigma(n)^2-sigma(n)^3+sigma(n)^4), n, NULL): seq(A259411(n), n=1..1000); # Wesley Ivan Hurt, Jul 09 2015
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MATHEMATICA
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Select[ Range[10000], PrimeQ[ 1 - DivisorSigma[1, #] + DivisorSigma[1, #]^2 - DivisorSigma[1, #]^3 + DivisorSigma[1, #]^4] & ]
Select[ Range[10000], PrimeQ[ Cyclotomic[10, DivisorSigma[1, #]]] &]
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PROG
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(MAGMA) [n: n in [1..600] | IsPrime(1 - DivisorSigma(1, n) + DivisorSigma(1, n)^2 - DivisorSigma(1, n)^3 + DivisorSigma(1, n)^4)]; // Vincenzo Librandi, Jun 27 2015
(PARI) is(n)=my(s=sigma(n)); isprime(s^4-s^3+s^2-s+1) \\ Charles R Greathouse IV, May 22 2017
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CROSSREFS
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Cf. A000203, A259410, A259412.
Sequence in context: A163324 A317186 A048204 * A058760 A239071 A085573
Adjacent sequences: A259408 A259409 A259410 * A259412 A259413 A259414
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KEYWORD
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easy,nonn
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AUTHOR
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Robert Price, Jun 26 2015
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STATUS
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approved
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