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 A143267 #2 Mar 30 2012 17:25:31 %S A143267 1,1,2,2,4,6,2,4,6,8,4,8,12,16,20,2,4,6,8,10,12,6,12,18,24,30,36,42,4, %T A143267 8,12,16,20,24,28,32,6,12,18,24,30,36,42,48,54,4,8,12,16,20,24,28,32, %U A143267 36,40,10,20,30,40,50,60,70,80,90,100 %N A143267 Triangle read by rows, A130207 * A000012 * A127648. %C A143267 Left border = phi(n), A000010. %C A143267 Row sums = A143268, phi(n)*T(n): (1, 3, 12, 20, 60, 42,...) %F A143267 Triangle read by rows, A130207 * A000012 * A127648; 1<=k<=n. T(n,k) = phi(n)*k. %e A143267 First few rows of the triangle = %e A143267 1; %e A143267 1, 2; %e A143267 2, 4, 6; %e A143267 2, 4, 6, 8; %e A143267 4, 8, 12, 16, 20; %e A143267 2, 4, 6, 8, 10, 12; %e A143267 6, 12, 18, 24, 30, 36, 42; %e A143267 4, 8, 12, 16, 20, 24, 28, 32; %e A143267 ... %e A143267 Row 5 = (4, 8, 12, 16, 20) since the first terms of phi(5) = 4; so we perform (4*1, 4*2, 4*3, 4*4, 4*5). %Y A143267 Cf. A130207, A127648, A000010. %K A143267 nonn,tabl %O A143267 1,3 %A A143267 _Gary W. Adamson_, Aug 03 2008