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 A143319 #8 Jun 10 2023 08:09:30 %S A143319 1,3,-1,4,-1,-1,7,-4,0,0,6,-1,-1,-1,-1,12,-8,-3,1,1,1,8,-1,-1,-1,-1, %T A143319 -1,-1,15,-11,0,0,0,0,0,0,13,-5,-5,0,0,0,0,0,0,18,-10,-3,-3,-3,1,1,1, %U A143319 1,1,12,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,28,-27,-7,4,4,4,0,0,0,0,0,0 %N A143319 Triangle read by rows, A051731 * A143318; 1<=k<=n. %C A143319 Left border = sigma(n), A000203. %C A143319 Right border = mu(n) A008683. %C A143319 Row sums = d(n), A000005. %e A143319 First few rows of the triangle = %e A143319 1; %e A143319 3, -1; %e A143319 4, -1, -1; %e A143319 7, -4, 0, 0; %e A143319 6, -1, -1, -1, -1; %e A143319 12, -8, -3, -1, -1, -1; %e A143319 8, -1, -1, -1, -1, -1, -1; %e A143319 ... %Y A143319 Cf. A000005, A000203, A008683, A051731, A143318. %K A143319 tabl,sign %O A143319 1,2 %A A143319 _Gary W. Adamson_, Aug 07 2008 %E A143319 a(69) = -7 corrected by _Georg Fischer_, Jun 10 2023