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Primes p such that there is prime q with sigma(q+2) = p.
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%I #15 Apr 27 2022 18:55:30

%S 7,13,31,1093,2801,5113,8011,17293,30103,30941,86143,459007,552793,

%T 579883,732541,1191373,3500201,3730693,4534771,5168803,5333791,

%U 7450171,10378063,25646167,25882657,28792661,30266503,43553401,48037081,52265671,56964757,62433703,65504743,67856407,76413823,77572057

%N Primes p such that there is prime q with sigma(q+2) = p.

%C Primes p such that there is prime q such that A000203(q+2) = p.

%C Primes p of the form sigma(A171130(n)) in increasing order.

%t Sort[Select[DivisorSigma[1,#+2]&/@Prime[Range[5200000]],PrimeQ]] (* _Harvey P. Dale_, Apr 27 2022 *)

%o (PARI) v=[];forprime(p=1,10^8,if(ispseudoprime(sigma(p+2)),v=concat(v,sigma(p+2))));v \\ _Derek Orr_, Oct 26 2014

%Y Cf. A000203, A008438, A171130, A247791, A247820, A247821, A247822, A247823, A247954.

%K nonn

%O 1,1

%A _Jaroslav Krizek_, Sep 28 2014

%E More terms from _Michel Marcus_, Oct 02 2014

%E Corrected and extended by _Harvey P. Dale_, Apr 27 2022