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 A143620 #5 Apr 10 2013 15:28:24 %S A143620 1,1,0,2,0,0,2,1,0,0,4,1,1,0,0,2,1,1,1,0,0,6,2,2,1,1,0,0,4,3,2,2,1,1, %T A143620 0,0,6,2,4,2,2,1,1,0,0,4,3,1,2,2,1,1,1,0,0,10,4,5,3,4,1,3,1,1,0,0,4,3, %U A143620 3,3,2,2,1,1,1,1,0,0 %N A143620 Triangle read by rows, square of A054521, 1<=k<=n. %C A143620 Left border = phi(n), A000010. %C A143620 Row sums = A053570: (1, 1, 2, 3, 6, 5, 12, 13,...). %F A143620 Triangle read by rows, square of A054521, 1<=k<=n %e A143620 First few rows of the triangle = %e A143620 1; %e A143620 1, 0; %e A143620 2, 0, 0; %e A143620 2, 1, 0, 0; %e A143620 4, 1, 1, 0, 0; %e A143620 2, 1, 1, 1, 0, 0; %e A143620 6, 2, 2, 1, 1, 0, 0; %e A143620 4, 3, 2, 2, 1, 1, 0, 0; %e A143620 6, 2, 4, 2, 2, 1, 1, 0, 0; %e A143620 ... %Y A143620 Cf. A054521, A000010, A053570. %K A143620 nonn,tabl %O A143620 1,4 %A A143620 _Gary W. Adamson_, Aug 27 2008