This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A043293 #10 Aug 12 2019 15:47:55 %S A043293 1,3,10,17,70,170,210,357,364,416,456,577,679,1092,1154,1358,1672, %T A043293 1705,1820,2280,2387,2565,2652,2835,2885,2910,3395,3570,4212,4577, %U A043293 4774,4947,5016,5044,5115,5130,5412,5670,5770,5863,6188,6790,7072,7161,7471,7546 %N A043293 Numbers n such that lcm(sigma(n),phi(n)) is a perfect square. %C A043293 If n is in the sequence and n>10 LCM(sigma(n),phi(n))==0 (mod 6) %H A043293 Amiram Eldar, <a href="/A043293/b043293.txt">Table of n, a(n) for n = 1..10000</a> %F A043293 n such that sqrt(A009286(n))=floor(sqrt(A009286(n))) %t A043293 Select[Range[8000], IntegerQ @ Sqrt @ LCM[EulerPhi[#], DivisorSigma[1, #]] &] (* _Amiram Eldar_, Aug 12 2019 *) %Y A043293 Cf. A009286. %K A043293 nonn %O A043293 1,2 %A A043293 _Benoit Cloitre_, Apr 04 2002