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 A268861 #13 Oct 11 2021 16:49:49
%S A268861 7,26,63,124,215,342,511,1330,1727,2196,2743,3374,4095,7999,9260,
%T A268861 10647,12166,13823,17575,19682,24388,26999,29790,32767,39303,42874,
%U A268861 46655,54871,59318,63999,74087,79506,85183,91124,103822,110591,124999,132650,140607,148876
%N A268861 Cubefree numbers n such that n + 1 is a perfect cube.
%C A268861 Intersection of A004709 and A068601. - _Michel Marcus_, Feb 15 2016
%H A268861 K. D. Bajpai, <a href="/A268861/b268861.txt">Table of n, a(n) for n = 1..400</a>
%e A268861 a(2) = 26 = 2 * 13 that is cubefree. 26 + 1 = 27 = 3^3 (perfect cube).
%e A268861 a(4) = 124 = 2 * 2 * 31 that is cubefree. 124 + 1 = 125 = 5^3 (perfect cube).
%p A268861 cubefree:= proc(n) local t;
%p A268861 max(seq(t[2],t=ifactors(n)[2])) <= 2
%p A268861 end proc:
%p A268861 select(cubefree, [seq(i^3-1,i=2..100)]); # _Robert Israel_, Mar 03 2016
%t A268861 Select[Range[150000], FreeQ[FactorInteger[#], {_, k_ /; k > 2}] && IntegerQ[CubeRoot[# + 1]] &]
%t A268861 Select[Range[2,70]^3,Max[FactorInteger[#-1][[All,2]]]<3&]-1 (* _Harvey P. Dale_, Oct 11 2021 *)
%o A268861 (PARI) for(n=1, 1e5, f = factor(n)[, 2]; if((#f == 0) || vecmax(f) < 3, if(ispower(n + 1, 3), print1(n, ", "))));
%Y A268861 Cf. A004709, A068601, A121628, A221793, A268752.
%K A268861 nonn
%O A268861 1,1
%A A268861 _K. D. Bajpai_, Feb 14 2016