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 A215567 #20 Jul 04 2021 14:12:14
%S A215567 3,13,20,42,44,45,56,60,86,87,112,119,121
%N A215567 Numbers k with the property that k and the k-th number which is a product of k primes have the largest prime divisor and with the same multiplicity.
%e A215567 13 and the 13th 13-almost prime = 13*2^12 = 53248 have same largest prime factor = 13, with the same multiplicity, so 13 is a term.
%t A215567 AlmostPrimePi[k_Integer,n_]:=...;AlmostPrime[k_,n_]:=...;
%t A215567 fQ[n_]:=FactorInteger[n][[-1,1]]==FactorInteger[AlmostPrime[n,n]][[-1,1]];k=1;lst={};
%t A215567 While[k<150,If[fQ@k,AppendTo[lst,k];Print@k];k++];lst (* _Robert G. Wilson v_, Aug 27 2012 *)
%Y A215567 Cf. A001222, A101695, A215405.
%K A215567 nonn,less
%O A215567 1,1
%A A215567 _Juri-Stepan Gerasimov_, Aug 16 2012
%E A215567 a(9)-a(13) from _Robert G. Wilson v_, Aug 27 2012
%E A215567 Definition clarified by _N. J. A. Sloane_, Sep 04 2012