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 A128306 #10 May 29 2023 13:20:01 %S A128306 1,1,0,2,1,0,2,2,1,0,4,6,4,1,0,2,4,6,4,1,0,6,15,20,15,6,1,0,4,12,22, %T A128306 24,16,6,1,0,6,21,45,60,51,27,8,1,0,4,16,44,76,85,62,29,8,1,0,10,45, %U A128306 120,210,252,210,120,45,10,1,0,4,20,66,144,226,258,211,120,45,10,1,0 %N A128306 Triangle read by rows: A054521 * A007318 as infinite lower triangular matrices. %C A128306 Left border = phi(n), A000010: (1, 1, 2, 2, 4, 2, 6, ...). Row sums = A054432: (1, 1, 3, 5, 15, 17, 63, ...). %e A128306 First few rows of the triangle: %e A128306 1; %e A128306 1, 0; %e A128306 2, 1, 0; %e A128306 2, 2, 1, 0; %e A128306 4, 6, 4, 1, 0; %e A128306 2, 4, 6, 4, 1, 0; %e A128306 6, 15, 20, 15, 6, 1, 0; %e A128306 ... %Y A128306 Cf. A000010, A007318, A054432, A054521. %K A128306 nonn,tabl %O A128306 1,4 %A A128306 _Gary W. Adamson_, Feb 25 2007 %E A128306 Definition amended and terms starting at a(56) corrected by _Georg Fischer_, May 29 2023