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 A372670 #27 May 30 2024 01:30:48 %S A372670 1,8,256,500,864,8192,9826,16000,27648,54000,132651,209952,246924, %T A372670 262144,314432,333396,512000,884736,1061208,1562500,1728000,6718464, %U A372670 7002306,7294032,7901568,8388608,8541936,10061824,10668672,13122000,13564278,15432750,16384000 %N A372670 Numbers k such that k * phi(k) is a fifth power. %C A372670 To look for terms it suffices to see if fifth powers have a divisors pair (k, m) such that phi(m) = k. - _David A. Corneth_, May 21 2024 %H A372670 David A. Corneth, <a href="/A372670/b372670.txt">Table of n, a(n) for n = 1..8846</a> (first 38 terms from R. J. Mathar) %F A372670 If n is in the sequence and prime p divides n, then p^5*n is in the sequence. %e A372670 8 * phi(8) = 32 = 2^5. %o A372670 (PARI) isok(n) = ispower(n*eulerphi(n), 5); %Y A372670 Cf. A000584, A002618, A114076. %K A372670 nonn %O A372670 1,2 %A A372670 _Seiichi Manyama_, May 10 2024