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 A143542 #2 Mar 30 2012 17:25:32 %S A143542 0,0,1,0,1,1,0,1,0,0,0,1,1,0,1,0,2,1,0,0,0,0,1,1,0,1,0,1,0,1,0,0,0,0, %T A143542 0,0,0,1,1,0,0,0,0,0,0,0,2,1,0,1,0,0,0,0,0,0,1,1,0,1,0,1,0,0,0,1 %N A143542 Triangle read by rows, A051731 * A143541 as infinite lower triangular matrices; 1<=k<=n. %C A143542 Row sums = A066328: (0, 1, 2, 1, 3, 3, 4,...) %C A143542 Prime rows = first n terms of A010051, the characteristic function of the primes. %F A143542 Triangle read by rows, A051731 * A143541 as infinite lower triangular matrices; 1<=k<=n. A051731 = the inverse Mobius transform. %e A143542 First few rows of the triangle = %e A143542 0; %e A143542 0, 1; %e A143542 0, 1, 1; %e A143542 0, 1, 0, 0; %e A143542 0, 1, 1, 0, 1; %e A143542 0, 2, 1, 0, 0, 0; %e A143542 0, 1, 1, 0, 1, 0, 1; %e A143542 ... %Y A143542 Cf. A143541, A051731, A010051. %K A143542 nonn,tabl %O A143542 1,17 %A A143542 _Gary W. Adamson_, Aug 23 2008