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 A194358 #16 Feb 27 2018 03:01:03
%S A194358 1,2,3,5,6,10,15,30,4,9,12,18,20,25,36,45,50,60,75,90,100,150,180,225,
%T A194358 300,450,900,8,24,27,40,54,72,108,120,125,135,200,216,250,270,360,375,
%U A194358 500,540,600,675,750,1000,1080,1125,1350,1500,1800,2250,2700,3000
%N A194358 Triangle of divisors of 30^n, each number occurring once.
%C A194358 The length of row k is A003215(k), the centered hexagonal numbers, 3k^2 + 3k + 1.
%H A194358 T. D. Noe, <a href="/A194358/b194358.txt">Table of n, a(n) for n=0..9260 (rows 0..20)</a>
%e A194358 The triangle has rows beginning with 2^k and ending with 30^k:
%e A194358 1
%e A194358 2, 3, 5, 6, 10, 15, 30
%e A194358 4, 9, 12, 18, 20, 25, 36, 45, 50, 60, 75, 90, 100, 150, 180, 225, 300, 450, 900
%t A194358 Join[{{1}}, Table[Complement[Divisors[30^n], Divisors[30^(n-1)]], {n, 9}]]
%Y A194358 Cf. A194356, A194357.
%Y A194358 Cf. A051037 (5-smooth numbers).
%K A194358 nonn,tabf
%O A194358 0,2
%A A194358 _T. D. Noe_, Aug 26 2011