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 A156839 #6 Jun 02 2025 01:23:50 %S A156839 1,1,1,1,1,1,2,2,1,1,1,1,1,1,1,5,5,3,1,1,1,1,1,1,1,1,1,1,6,6,4,4,1,1, %T A156839 1,1,6,6,6,1,1,1,1,1,1,1,9,9,5,5,5,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,24, %U A156839 24,22,15,6,6,1,1,1,1,1,1 %N A156839 Triangle read by rows, A054525 * A156348 * A000012. %C A156839 For rows >1, n-th row = all 1's iff n is prime. %C A156839 Row sums = A156833: (1, 2, 3, 6, 5, 16, 7, 24, 24, 38, 11,...). %F A156839 Triangle read by rows, A054525 * A156348 * A000012 A054525 = the inverse Mobius transform, A000012 = an infinite lower triangular matrix with all 1's. %e A156839 First few rows of the triangle = %e A156839 1; %e A156839 1, 1; %e A156839 1, 1, 1; %e A156839 2, 2, 1, 1; %e A156839 1, 1, 1, 1, 1; %e A156839 5, 5, 3, 1, 1, 1; %e A156839 1, 1, 1, 1, 1, 1, 1; %e A156839 6, 6, 4, 4, 1, 1, 1, 1; %e A156839 6, 6, 6, 1, 1, 1, 1, 1, 1; %e A156839 9, 9, 5, 5, 5, 1, 1, 1, 1, 1; %e A156839 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1; %e A156839 24, 24, 22, 15, 6, 6, 1, 1, 1, 1, 1, 1; %e A156839 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1; %e A156839 13, 13, 7, 7, 7, 7, 7, 1, 1, 1, 1, 1, 1, 1; %e A156839 ... %Y A156839 Cf. A156348, A054525, A156833 %K A156839 nonn,tabl %O A156839 1,7 %A A156839 _Gary W. Adamson_ and _Mats Granvik_, Feb 16 2009