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 A144736 #5 Jun 02 2025 00:36:15 %S A144736 1,2,1,2,0,2,3,0,2,2,2,-2,1,1,4,4,-2,3,0,5,2,2,-4,0,-1,4,1,6,4,-5,2, %T A144736 -1,4,1,6,4,3,-6,1,-3,4,-2,6,4,6,4,-8,0,-4,8,-3,7,3,7,4,2,-8,-2,-6,3, %U A144736 -4,6,2,6,3,10 %N A144736 Triangle read by rows, A051731 * A000012 * A051731 * A054533. %C A144736 Row sums = sigma(n), A000203. %C A144736 Right border = phi(n), A000010 %C A144736 Left border = d(n), A000005 %F A144736 Triangle read by rows, A051731 * A000012 * A051731 * A054533; as infinite lower triangular matrices. %e A144736 First few rows of the triangle = %e A144736 1; %e A144736 2, 1; %e A144736 2, 0, 2; %e A144736 3, 0, 2, 2; %e A144736 2, -2, 1, 1, 4; %e A144736 4, -2, 3, 0, 5, 2; %e A144736 2, -4, 0, -1, 4, 1, 6; %e A144736 4, -5, 2, -1, 4, 1, 6, 4; %e A144736 3, -6, 1, -3, 4, -2, 6, 4, 6; %e A144736 4, -8, 0, -4, 8, -3, 7, 3, 7, 4; %e A144736 ... %Y A144736 A054533, Cf. A000203, A000005, A000010, A051731 %K A144736 tabl,sign %O A144736 1,2 %A A144736 _Gary W. Adamson_, Sep 20 2008