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%I #15 Sep 08 2022 08:46:10
%S 24001,95881,205633,2266177,3792673,3850393,6846241,7448641,15498121,
%T 21566497,25267681,28987681,48114841,57207697,69805261,79176001,
%U 90257521,110360641,121223761,129642001,139752001,164655793,166175461,185983981,211268881,264159601
%N Primes p such that (p-1)/2 and p+1 have the same sum of divisors.
%e 24001 is in this sequence because A000203((24001-1)/2) = A000203(24001+1) = 39312 and 24001 is prime.
%t Select[Prime[Range[1442*10^4]],DivisorSigma[1,(#-1)/2]==DivisorSigma[ 1,#+1]&] (* _Harvey P. Dale_, Dec 13 2018 *)
%o (Magma) [p: p in PrimesInInterval(3, 100000000) | SumOfDivisors((p-1) div 2) eq SumOfDivisors(p+1)];
%o (PARI) forprime(p=3, 10^8, if(sigma((p-1)\2)==sigma(p+1), print1(p, ", "))) \\ _Colin Barker_, Nov 02 2014
%Y Cf. A000203, A171720, A249511.
%K nonn
%O 1,1
%A _Juri-Stepan Gerasimov_, Nov 02 2014
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