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 A078169 #13 Apr 24 2020 11:01:59
%S A078169 1,2,771,1024,1028,1088,1280,1360,1536,1542,1632,1920,2040,327685,
%T A078169 524288,524296,526336,557056,559232,655360,655370,657920,696320,
%U A078169 699040,786432,786444,789504,835584,838848,983040,986880,1044480,1048560
%N A078169 Numbers k such that phi(k) is a perfect 9th power.
%H A078169 Amiram Eldar, <a href="/A078169/b078169.txt">Table of n, a(n) for n = 1..10000</a>
%e A078169 phi of the sequence includes 1, 512, 262144,.. etc.; powers arise several times; a(3) = A053576(9) = 771; in sequence smoother ranges and quite large jumps arise when power of new numbers appear as phi-values.
%t A078169 k=9; Do[s=EulerPhi[n]^(1/k); If[IntegerQ[s], Print[n]], {n, 1, 10000000}]
%o A078169 (PARI) is(n)=ispower(eulerphi(n),9) \\ _Charles R Greathouse IV_, Apr 24 2020
%Y A078169 Cf. A039770 (square), A039771 (cube), A078164 (4th), A078165 (5th), A078166 (6th), A078167 (7th), A078168 (8th), A078169 (9th, this sequence), A078170 (10th power), A001317, A053576, A045544, A000010.
%K A078169 nonn
%O A078169 1,2
%A A078169 _Labos Elemer_, Nov 27 2002