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 A084549 #8 Oct 07 2021 02:06:06
%S A084549 2,131,139,149,163,169,173,179,181,227,243,269,293,317,347,349,361,
%T A084549 373,389,419,443,461,467,509,523,541,557,563,587,613,619,625,653,661,
%U A084549 677,709,729,773,787,797,821,829,853,859,877,907,941,947,1019,1061,1091,1109
%N A084549 Numbers k that have primitive roots less than k that are nonnegative perfect seventh powers.
%H A084549 Amiram Eldar, <a href="/A084549/b084549.txt">Table of n, a(n) for n = 1..10000</a>
%t A084549 q[n_] := Intersection[PrimitiveRootList[n], Range[Floor@Surd[n, 7]]^7] != {}; Select[Range[1000], q] (* _Amiram Eldar_, Oct 07 2021 *)
%Y A084549 Cf. A001015, A084547, A084548, A084550.
%K A084549 nonn
%O A084549 1,1
%A A084549 Hauke Worpel (hw1(AT)email.com), May 30 2003
%E A084549 a(1) inserted and more terms added by _Amiram Eldar_, Oct 07 2021