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 A181101 #2 Mar 30 2012 18:53:10 %S A181101 -1,1,0,1,0,0,0,1,0,0,1,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0, %T A181101 0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0, %U A181101 0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0 %N A181101 Triangle T(n,k) read by rows. T(1,1)=-1, n>1: If n/k=A020639(n) then 1 else 0. %C A181101 Let A=T(n,k)*T(n,k), B=A*A, C=B*B, D=C*C, and so on. Then the first column in the last matrix (D) converges to the Liouville function. %e A181101 Triangle starts: %e A181101 -1, %e A181101 1,0, %e A181101 1,0,0, %e A181101 0,1,0,0, %e A181101 1,0,0,0,0, %e A181101 0,0,1,0,0,0, %e A181101 1,0,0,0,0,0,0, %e A181101 0,0,0,1,0,0,0,0, %e A181101 0,0,1,0,0,0,0,0,0, %e A181101 0,0,0,0,1,0,0,0,0,0, %e A181101 1,0,0,0,0,0,0,0,0,0,0, %e A181101 0,0,0,0,0,1,0,0,0,0,0,0, %Y A181101 Cf. A020639, A008836. %K A181101 sign,tabl %O A181101 1,1 %A A181101 _Mats Granvik_, Oct 03 2010