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 A384419 #8 May 28 2025 10:52:08
%S A384419 1,2,3,4,5,7,8,9,11,13,17,19,23,25,27,29,31,32,37,41,43,47,49,53,59,
%T A384419 61,64,67,71,73,79,83,89,97,101,103,107,109,113,121,125,127,128,131,
%U A384419 137,139,149,151,157,163,167,169,173,179,181,191,193,197,199,211,223
%N A384419 Exponentially squarefree prime powers.
%C A384419 Differs from A283262 by having the terms 1, 128, 1024, 2187, 8192, ..., and not having the terms 256, 512, 6561, ... .
%C A384419 1 and numbers of the form p^e where p is prime and e is a squarefree number.
%H A384419 Amiram Eldar, <a href="/A384419/b384419.txt">Table of n, a(n) for n = 1..10000</a>
%t A384419 seq[lim_] := Module[{s = Select[Range[lim], !CompositeQ[#] &]}, Do[If[SquareFreeQ[i], s = Join[s, Select[Range[Surd[lim, i]], PrimeQ]^i]], {i, 2, Floor[Log2[lim]]}]; Sort[s]]; seq[250]
%Y A384419 Intersection of A000961 and A209061.
%Y A384419 Disjoint union of {1}, A000040 and A383211.
%Y A384419 Cf. A005117, A283262.
%K A384419 nonn,easy
%O A384419 1,2
%A A384419 _Amiram Eldar_, May 28 2025