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%I #12 Sep 23 2019 13:27:27
%S 3,5,6,7,9,10,11,14,15,17,18,22,24,26,28,29,30,31,33,34,35,44,47,50,
%T 56,58,61,65,66,67,68,69,71,72,74,75,80,85,91,94,96,97,100,101,102,
%U 104,116,118,120,121,124,125,127,131,134,136,139,144,148,149,152,164,166,170
%N Numbers n for which the absolute value of the abundance of n^2 is a prime number.
%H Amiram Eldar, <a href="/A125236/b125236.txt">Table of n, a(n) for n = 1..10000</a>
%e n=5: n^2=25, sigma(25)=25+5+1=31, 2*25=50, abundance=-19.
%t Select[Range[170], PrimeQ[DivisorSigma[1, #^2] - 2*#^2] &] (* _Amiram Eldar_, Sep 23 2019 *)
%o (PARI) for(n=1,170,if(isprime(abs(sigma(n^2)-2*n^2)),print1(n,","))) \\ _Klaus Brockhaus_, Nov 25 2006
%Y Cf. A088005.
%K nonn
%O 1,1
%A _Jason G. Wurtzel_, Nov 25 2006
%E More terms from _Klaus Brockhaus_, Nov 25 2006
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