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 A114078 #20 Sep 08 2022 08:45:23 %S A114078 1,170,595,714,121056,480441,529620,706063,706237,729752,755972, %T A114078 815654,2162808,2449062,2827789,2927848,2957416,2994681,2995419, %U A114078 3010227,3019028,3019772,3080140,3093860,3103464,3206364,3213804 %N A114078 Numbers k such that phi(k)*sigma(k) is a fourth power. %D A114078 J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 170, p. 54, Ellipses, Paris 2008. %H A114078 Amiram Eldar, <a href="/A114078/b114078.txt">Table of n, a(n) for n = 1..600</a> %e A114078 phi(595) * sigma(595) = 331776 = 24^4. %t A114078 Select[Range[3300000],IntegerQ[Power[EulerPhi[#] DivisorSigma[1,#], (4)^-1]]&] (* _Harvey P. Dale_, Mar 14 2011 *) %o A114078 (PARI) isok(n) = ispower(eulerphi(n)*sigma(n), 4); \\ _Michel Marcus_, Jan 09 2014 %o A114078 (Magma) [k:k in [1..3300000]| IsPower(EulerPhi(k)*DivisorSigma(1,k),4)]; // _Marius A. Burtea_, Sep 19 2019 %Y A114078 Cf. A062354, subsequence of A011257. %K A114078 nonn %O A114078 1,2 %A A114078 _Giovanni Resta_, Feb 13 2006