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 A332008 #16 Sep 08 2022 08:46:25
%S A332008 1,15,16,63,101,125,255,256,272,504,512,513,629,679,1358,1359,1728,
%T A332008 1970,2047,2222,2509,2834,3458,3705,4094,4095,4400,4577,4616,4913,
%U A332008 5403,6817,7295,7956,8729,11667,11672,16132,16384,16523,17507,23085,24198,24564,24624,25220,25601,27216,27384,28564,29444
%N A332008 Numbers k such that phi(k) and phi(k+1) are perfect powers (A001597).
%e A332008 phi(101) = 10^2, and phi(102) = 2^5.
%e A332008 phi(3458) = 6^4, and phi(3459) = 48^2.
%t A332008 perfectPowerQ[1] = True; perfectPowerQ[n_] := GCD @@ FactorInteger[n][[;; , 2]] > 1; Select[Range[30000], And @@ perfectPowerQ /@ EulerPhi[# + {0, 1}] &] (* _Amiram Eldar_, Feb 04 2020 *)
%o A332008 (PARI) v=[1]; for(i = 2, 30000, if(ispower(eulerphi(i)), if(ispower(eulerphi(i+1)), v = concat(v, i)))); v
%o A332008 (Magma) [1] cat [k:k in [3..30000]|IsPower(EulerPhi(k)) and IsPower(EulerPhi(k+1))]; // _Marius A. Burtea_, Feb 05 2020
%Y A332008 Cf. A000010, A001597, A166955, A281016.
%K A332008 nonn
%O A332008 1,2
%A A332008 _Antonio Roldán_, Feb 04 2020