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 A111470 #7 Jul 20 2019 11:13:06
%S A111470 1,2,3,4,5,6,7,8,9,10,11,12,18,13,14,15,16,17,18,12,19,20,50,21,22,23,
%T A111470 24,54,25,26,27,28,98,29,30,31,32,33,34,35,36,37,38,39,40,250,41,42,
%U A111470 43,44,242,45,75,46,47,48,162,49,20,50,51,52,338,53,24,54,55
%N A111470 Irregular table read by rows: the n-th row gives all the numbers with the prime signature of n using only prime divisors of n.
%C A111470 If n is a perfect power of a squarefree number then it contributes only one term.
%e A111470 18 follows 12 as 12=2^2*3 and 18 = 3^2*2.
%t A111470 a[n_] := Module[{f = FactorInteger[n]}, p = f[[;; , 1]]; e = f[[;; , 2]]; Times @@ Power[p, #] & /@ Permutations[e]]; s = {}; Do[s = Join[s, a[n]], {n, 1, 55}]; s (* _Amiram Eldar_, Jul 20 2019 *)
%K A111470 easy,nonn,tabf
%O A111470 1,2
%A A111470 _Amarnath Murthy_, Aug 05 2005
%E A111470 More terms from _Amiram Eldar_, Jul 20 2019