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 A191973 #14 Mar 31 2012 13:22:30
%S A191973 1,2,1,2,3,4,6,2,3,4,6,12,2,3,4,5,6,8,12,20,4,5,6,10,30,2,3,4,5,6,7,8,
%T A191973 9,10,12,15,18,24,42,6,7,8,14,56,4,6,7,8,9,10,12,16,24,40,72,6,8,9,10,
%U A191973 12,18,36,90,5,6,8,9,10,11,12,14,15,20,30,35,60
%N A191973 Irregular triangle read by rows: row n consists of n and the positive integers m where m-n divides m*n.
%C A191973 The maximum term of the n-th row is n*(n+1). The minimum term of the n-th row seems to be A063428(n) if n>=2. The length of row n is A146564(n) + 1.
%H A191973 Nathaniel Johnston, <a href="/A191973/b191973.txt">Rows 1..250, flattened</a>
%e A191973 The triangle begins:
%e A191973 1 2
%e A191973 1 2 3 4 6
%e A191973 2 3 4 6 12
%e A191973 2 3 4 5 6 8 12 20
%e A191973 4 5 6 10 30
%e A191973 2 3 4 5 6 7 8 9 10 12 15 18 24 42
%e A191973 6 7 8 14 56
%e A191973 ...
%p A191973 for n from 1 to 10 do for m from 1 to n*(n+1) do if(n=m or m*n mod (m-n) = 0)then printf("%d, ",m): fi: od: od:
%Y A191973 Cf. A162821 (row 30), A162822 (row 36), A162823 (row 42), A162824 (row 48), A162825 (row 60), A127730.
%K A191973 nonn,easy,tabf
%O A191973 1,2
%A A191973 _Nathaniel Johnston_, Jun 22 2011