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 A159937 #2 Mar 30 2012 17:25:34 %S A159937 1,1,1,2,0,2,2,1,0,2,4,0,0,0,4,2,2,2,0,0,2,6,0,0,0,0,0,6,4,2,0,2,0,0, %T A159937 0,4,6,0,4,0,0,0,0,0,6,4,4,0,0,4,0,0,0,0,4,10,0,0,0,0,0,0,0,0,0,10,4, %U A159937 2,4,4,0,2,0,0,0,0,0,4 %N A159937 Triangle read by rows, A054525 * A127478, as infinite lower triangular matrices. %C A159937 Row sums = A029935: (1, 2, 4, 5, 8, 8,...). Right and left borders = A000010, phi(n). %F A159937 A054525 * A127478 = Mobius transform of triangle A127478. %e A159937 First few rows of the triangle = %e A159937 1; %e A159937 1, 1; %e A159937 2, 0, 2; %e A159937 2, 1, 0, 2; %e A159937 4, 0, 0, 0, 4; %e A159937 2, 2, 2, 0, 0, 2; %e A159937 6, 0, 0, 0, 0, 0, 6; %e A159937 4, 2, 0, 2, 0, 0, 0, 4; %e A159937 6, 0, 4, 0, 0, 0, 0, 0, 6; %e A159937 4, 4, 0, 0, 4, 0, 0, 0, 0, 4; %e A159937 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10; %e A159937 4, 2, 4, 4, 0, 2, 0, 0, 0, 0, 0, 4; %e A159937 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12; %e A159937 6, 6, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 6; %e A159937 8, 0, 8, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8; %e A159937 ... %Y A159937 Cf. A127478, A029935 %K A159937 nonn,tabl %O A159937 1,4 %A A159937 _Gary W. Adamson_, Apr 26 2009