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 A127444 #5 Mar 30 2012 17:25:15
%S A127444 1,2,-2,2,-2,0,3,-4,0,1,2,-2,0,1,-1,4,-6,0,1,-1,2,2,-2,0,1,-1,2,-2,4,
%T A127444 -6,0,2,-1,2,-2,1,3,-4,0,1,-1,2,-2,1,0,4,-6,0,2,-2,2,-2,1,0,1,2,-2,0,
%U A127444 1,-1,2,-2,1,0,1,-2,6,-10,0,3,-2,4,-2,1
%N A127444 Triangle defined as the matrix product A051731*A127442, read by rows.
%C A127444 Row sums = 0.
%F A127444 T(n,k) = sum_{j=k..n} A051731(n,j)*A127442(j,k) = sum_{j=k..n, j|n} A127442(j,k), 1<=k<=n.
%e A127444 First few rows of the triangle are:
%e A127444 1;
%e A127444 2, -2;
%e A127444 2, -2, 0;
%e A127444 3, -4, 0, 1;
%e A127444 2, -2, 0, 1, -1;
%e A127444 4, -6, 0, 1, -1, 2;
%e A127444 2, -2, 0, 1, -1, 2, -2;
%e A127444 ...
%Y A127444 Cf. A000005 (column k=1), A051731, A127442.
%K A127444 tabl,easy,sign
%O A127444 1,2
%A A127444 _Gary W. Adamson_, Jan 14 2007