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 A187954 #6 Jul 22 2025 10:57:27 %S A187954 1,1,3,1,0,5,1,0,0,7,1,3,0,0,9,1,0,0,0,0,11,1,0,0,0,0,0,13,1,3,5,0,0, %T A187954 0,0,15,1,0,0,0,0,0,0,0,17,0,0,0,0,0,0,0,0,19,1,3,0,7,0,0,0,0,0,0,21 %N A187954 Triangle by rows, divisors of odd integers. %C A187954 Row sums = A008438: (1, 4, 6, 8, 13, 12, 14,...) %F A187954 Let A = A114000 and B = a diagonalized variant of the odd integers ((1, 3, 5, 7, 9,...) as the right diagonal and the rest zeros). The triangle = A*B as infinite lower triangular matrices. %e A187954 First few rows of the triangle = %e A187954 1 %e A187954 1, 3 %e A187954 1, 0, 5 %e A187954 1, 0, 0, 7 %e A187954 1, 3, 0, 0, 9 %e A187954 1, 0, 0, 0, 0, 11 %e A187954 1, 0, 0, 0, 0, 0, 13 %e A187954 1, 3, 5, 0, 0, 0, 0, 15 %e A187954 1, 0, 0, 0, 0, 0, 0, 0, 17 %e A187954 1, 0, 0, 0, 0, 0, 0, 0, 0, 19 %e A187954 1, 3, 0, 7, 0, 0, 0, 0, 0, 0, 21 %e A187954 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 23 %e A187954 1, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 25 %e A187954 1, 3, 0, 0, 9, 0, 0, 0, 0, 0, 0, 0, 0, 27 %e A187954 ... %e A187954 Example: Row 4 = (1, 3, 0, 0, 9) since the divisors of 9 are (1, 3, and 9). %Y A187954 Cf. A114000, A008438 %K A187954 nonn,tabl %O A187954 0,3 %A A187954 _Gary W. Adamson_, Mar 16 2011