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 A143594 #2 Mar 30 2012 17:25:32 %S A143594 1,2,2,2,2,2,3,4,2,2,2,2,2,2,2,4,6,4,2,2,2,2,2,2,2,2,2,2,4,6,4,4,2,2, %T A143594 2,2,3,4,4,2,2,2,2,2,2,4,6,4,4,4,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,6,10, %U A143594 8,6,4,4,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2 %N A143594 Triangle read by rows, A051731 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's). %C A143594 Left column = d(n), A000005: (1, 2, 2, 3, 2, 4, 2,...). %C A143594 Prime rows have all 2's. %C A143594 Row sums = A129235: (1, 4, 6, 11, 10, 10,...). %F A143594 Triangle read by rows, A051731 * (an infinite lower triangular matrix with 1's in the first column and the rest 2's), i.e. (1; 1,2; 1,2,2;...), 1<=k<=n A051731 = the inverse Mobius transform. %e A143594 First few rows of the triangle = %e A143594 1; %e A143594 2, 2; %e A143594 2, 2, 2; %e A143594 3, 4, 2, 2; %e A143594 2, 2, 2, 2, 2; %e A143594 4, 6, 4, 2, 2, 2; %e A143594 2, 2, 2, 2, 2, 2, 2; %e A143594 ... %Y A143594 Cf. A129235, A000005, A051731. %K A143594 nonn,tabl %O A143594 1,2 %A A143594 _Gary W. Adamson_, Aug 26 2008