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 A143613 #8 Jun 05 2023 07:07:07 %S A143613 1,2,0,2,2,0,3,0,3,0,2,2,3,4,0,4,2,0,0,5,0,2,2,3,4,5,6,0,4,0,6,0,5,0, %T A143613 7,0,3,4,0,4,5,0,7,8,0,4,2,6,4,0,0,7,0,9,0,2,2,3,4,5,6,7,8,9,10,0,6,2, %U A143613 3,0,10,0,7,0,0,0,11,0,2,2,3,4,5,6,7,8,9,10,11,12,0 %N A143613 Triangle read by rows: A051731 * A127368. %C A143613 A051731 = the inverse Moebius transform. %C A143613 A127368 records the reduced residue system mod n, by rows. %C A143613 Left border = d(n). %C A143613 Row sums = A057661: (1, 2, 4, 6, 11, 11, 22, 22, 31, ...). %e A143613 First few rows of the triangle; %e A143613 1; %e A143613 2, 0; %e A143613 2, 2, 0; %e A143613 3, 0, 3, 0; %e A143613 2, 2, 3, 4, 0; %e A143613 4, 2, 0, 0, 5, 0; %e A143613 2, 2, 3, 4, 5, 6, 0; %e A143613 ... %Y A143613 Cf. A000005, A051731, A057661, A127368. %K A143613 nonn,tabl %O A143613 1,2 %A A143613 _Gary W. Adamson_, Aug 27 2008 %E A143613 a(78) = 0 inserted by _Georg Fischer_, Jun 05 2023