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%I #10 Apr 21 2019 12:10:51
%S 1,2,36,100,108,128,196,225,256,288,441,450,484,600,675,676,800,864,
%T 882,1089,1156,1176,1225,1296,1323,1350,1444,1521,1568,1944,2000,2116,
%U 2178,2450,2601,2646,2904,3025,3042,3240,3249,3267,3364,3844,3872,4056
%N Numbers n such that n*tau(n) is a perfect square.
%H Harvey P. Dale, <a href="/A069067/b069067.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[4200],IntegerQ[Sqrt[# DivisorSigma[0,#]]]&] (* _Harvey P. Dale_, Apr 21 2019 *)
%K easy,nonn
%O 1,2
%A _Benoit Cloitre_, Apr 05 2002