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 A139308 #18 Nov 24 2021 04:11:56
%S A139308 729,2187,29791,50625,50653,83521,130321,132651,166375,185193,226981,
%T A139308 300763,707281,804357,823543,1295029,1860867,1874161,2685619,3176523,
%U A139308 4782969,5545233,5764801,7189057,9393931,12977875,13845841,16194277
%N A139308 Lucky numbers that are pure (perfect) powers with exponent greater than 2.
%C A139308 Intersection of A000959 and A076467.
%H A139308 Kevin P. Thompson, <a href="/A139308/b139308.txt">Table of n, a(n) for n = 1..113</a> (terms < 10^10 with terms 1..94 from Giovanni Resta)
%e A139308 a(1) = 729 = 3^6 and 729 is lucky, i.e., A000959(118) = 729.
%t A139308 t = 2 Range@ 10000000 - 1; f[n_] := Block[{k = t[[n]]}, t = Delete[t, Table[{k}, {k, k, Length@t, k}]]]; Do[f@n, {n, 2, 1000000}]; fQ[n_] := ! IntegerQ@ Log[2, n] && GCD @@ Last /@ FactorInteger@n > 2; Select[t, fQ] (* _Robert G. Wilson v_, Oct 16 2010 *)
%Y A139308 Cf. A000959, A076467, A031162.
%K A139308 nonn
%O A139308 1,1
%A A139308 _Walter Kehowski_, Jun 07 2008
%E A139308 a(16)-a(28) from _Robert G. Wilson v_, Oct 16 2010