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A247955
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Primes p such that there is prime q with sigma(q+2) = p.
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0
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7, 13, 31, 1093, 2801, 5113, 8011, 17293, 30103, 30941, 86143, 459007, 552793, 579883, 732541, 1191373, 3500201, 3730693, 4534771, 5168803, 5333791, 7450171, 10378063, 25646167, 25882657, 28792661, 30266503, 43553401, 48037081, 52265671, 56964757, 62433703, 65504743, 67856407, 76413823, 77572057
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OFFSET
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1,1
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COMMENTS
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Primes p such that there is prime q such that A000203(q+2) = p.
Primes p of the form sigma(A171130(n)) in increasing order.
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LINKS
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MATHEMATICA
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Sort[Select[DivisorSigma[1, #+2]&/@Prime[Range[5200000]], PrimeQ]] (* Harvey P. Dale, Apr 27 2022 *)
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PROG
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(PARI) v=[]; forprime(p=1, 10^8, if(ispseudoprime(sigma(p+2)), v=concat(v, sigma(p+2)))); v \\ Derek Orr, Oct 26 2014
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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