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%I #26 Feb 20 2023 19:52:35
%S 2,3,5,6,7,9,11,13,15,17,19,23,25,29,30,31,33,37,41,43,44,47,49,51,53,
%T 59,61,67,69,71,73,79,81,83,87,89,91,97,101,103,107,109,113,114,117,
%U 120,121,123,124,127,131,133,135,137,139,141,149,151,157,159
%N Average of divisors except itself is an integer.
%C All the prime numbers (A000040) are in this sequence. But there are other numbers (A023885). - _Daniel Lignon_, Feb 26 2015
%H Daniel Lignon, <a href="/A023884/b023884.txt">Table of n, a(n) for n = 1..1000</a>
%p q:=n->(irem(numtheory[sigma](n)-n,numtheory[tau](n)-1)=0):
%p select(q,[$2..159])[]; # _Lorenzo Sauras Altuzarra_, Feb 01 2023
%t Select[Range[2000],IntegerQ[Mean[Most[Divisors[#]]]]&] (* _Daniel Lignon_, Feb 26 2015 *)
%o (PARI) isok(n) = (n != 1) && !((sigma(n) - n) % (numdiv(n)-1)); \\ _Michel Marcus_, Mar 01 2015
%Y Cf. A000040, A023885.
%K nonn
%O 1,1
%A _Olivier Gérard_
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