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 A143320 #5 Apr 10 2013 15:27:38 %S A143320 1,4,-1,8,-1,-1,15,-4,-1,0,21,-4,-1,0,-1,33,-8,-4,0,-1,1,41,-8,-4,0, %T A143320 -1,1,-1,56,-15,-4,0,-1,1,-1,0,69,-15,-8,0,-1,1,-1,0,0,87,-21,-8,0,-4, %U A143320 1,-1,0,0,1,99,-21,-8,0,-4,1,-1,0,0,1,-1,127,-33,-15,0,-4,4,-1,0,0,1,-1,0 %N A143320 Triangle read by rows, A000012 * A143317; 1<=k<=n. %C A143320 Left border = A024916: (1, 4, 8, 15, 21, 33,...). %C A143320 Right border = mu(n), A008683. %C A143320 Row sums = T(n), triangular numbers. %F A143320 Triangle read by rows, A000012 * A143317; 1<=k<=n %e A143320 First few rows of the triangle = %e A143320 1; %e A143320 4, -1; %e A143320 8, -1, -1 %e A143320 15, -4, -1, 0; %e A143320 21, -4, -1, 0, -1; %e A143320 33, -8, -4, 0, -1, 1; %e A143320 41, -3, -4, 0, -1, 1, -1; %e A143320 ... %Y A143320 Cf. A143317, A008683, A024916. %K A143320 sign,tabl %O A143320 1,2 %A A143320 _Gary W. Adamson_, Aug 07 2008 %E A143320 Corrected last few terms. - Stuart Orford (sjorford(AT)gmail.com), Dec 22 2008