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 A158946 #4 Jun 02 2025 01:28:17 %S A158946 1,1,1,2,1,2,2,2,1,3,3,2,3,1,4,3,3,2,4,1,5,4,3,4,2,5,1,6,4,4,3,5,2,6, %T A158946 1,7,5,4,5,3,6,2,7,1,8,5,5,4,6,3,7,2,8,1,9,6,5,6,4,7,3,8,2,9,1,10,6,6, %U A158946 5,7,4,8,3,9,2,10,1,11 %N A158946 Triangle read by rows, A000012(signed) * A145677 * A000012. %C A158946 Row sums = A000982 starting with offset 1: (1, 2, 5, 8, 13, 18, 25,...). %F A158946 Triangle read by rows, A000012(signed) * A145677 * A000012. A000012(signed) = an infinite lower triangular matrix with (1,-1,1,-1,...) in every column. A145677 = an infinite lower triangular matrix with all 1's as the left border, right border = (1, 1, 2, 3, 4, 5,...), and the rest zeros. %e A158946 First few rows of the triangle = %e A158946 1; %e A158946 1, 1; %e A158946 2, 1, 2; %e A158946 2, 2, 1, 3; %e A158946 3, 2, 3, 1, 4; %e A158946 3, 3, 2, 4, 1, 5; %e A158946 4, 3, 4, 2, 5, 1, 6; %e A158946 4, 4, 3, 5, 2, 6, 1, 7; %e A158946 5, 4, 5, 3, 6, 2, 7, 1, 8; %e A158946 5, 5, 4, 6, 3, 7, 2, 8, 1, 9; %e A158946 6, 5, 6, 4, 7, 3, 8, 2, 9, 1, 10; %e A158946 6, 6, 5, 7, 4, 8, 3, 9, 2, 10, 1, 11; %e A158946 7, 6, 7, 5, 8, 4, 9, 3, 10, 2, 11, 1, 12; %e A158946 7, 7, 6, 8, 5, 9, 4, 10, 3, 11, 2, 12, 1, 13; %e A158946 ... %Y A158946 Cf. A145677, A000982 %K A158946 nonn,tabl %O A158946 1,4 %A A158946 _Gary W. Adamson_, Mar 31 2009