%I
%S 1,3,10,17,70,170,210,357,364,416,456,577,679,1092,1154,1358,1672,
%T 1705,1820,2280,2387,2565,2652,2835,2885,2910,3395,3570,4212,4577,
%U 4774,4947,5016,5044,5115,5130,5412,5670,5770,5863,6188,6790,7072,7161,7471,7546
%N Numbers n such that lcm(sigma(n),phi(n)) is a perfect square.
%C If n is in the sequence and n>10 LCM(sigma(n),phi(n))==0 (mod 6)
%H Amiram Eldar, <a href="/A043293/b043293.txt">Table of n, a(n) for n = 1..10000</a>
%F n such that sqrt(A009286(n))=floor(sqrt(A009286(n)))
%t Select[Range[8000], IntegerQ @ Sqrt @ LCM[EulerPhi[#], DivisorSigma[1, #]] &] (* _Amiram Eldar_, Aug 12 2019 *)
%Y Cf. A009286.
%K nonn
%O 1,2
%A _Benoit Cloitre_, Apr 04 2002
