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 A127476 #5 Sep 18 2013 03:39:22
%S A127476 1,1,0,2,1,0,2,0,2,0,4,2,2,2,0,2,0,0,0,4,0,6,3,4,2,4,2,0,4,0,2,0,4,0,
%T A127476 6,0,6,3,0,4,4,0,6,4,0,4,0,4,0,0,0,6,0,6,0,10,5,6,4,8,2,6,4,6,4,0,4,0,
%U A127476 0,0,4,0,6,0,0,0,10,0
%N A127476 Triangle T(n,k) = sum_{j=k..n, gcd(n,j)=1, k|j} phi(k).
%F A127476 T(n,k) = sum_{j=k..n} A054521(n,j) * A054522(j,k), product of the two infinite lower triangular matrices.
%F A127476 T(n,1) = A000010(n).
%e A127476 First few rows of the triangle are:
%e A127476 1;
%e A127476 1, 0;
%e A127476 2, 1, 0;
%e A127476 2, 0, 2, 0;
%e A127476 4, 2, 2, 2, 0;
%e A127476 2, 0, 0, 0, 4, 0;
%e A127476 6, 3, 4, 2, 4, 2, 0;
%e A127476 4, 0, 2, 0, 4, 0, 6, 0;
%e A127476 ...
%Y A127476 Cf. A054521, A054522, A023896 (row sums), A000010.
%K A127476 nonn,tabl
%O A127476 1,4
%A A127476 _Gary W. Adamson_, Jan 15 2007