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 A176890 #5 Apr 25 2016 11:44:15 %S A176890 -1,1,0,1,0,0,1,1,0,0,1,0,0,0,0,1,1,1,0,0,0,1,0,0,0,0,0,0,1,1,0,1,0,0, %T A176890 0,0,1,0,1,0,0,0,0,0,0,1,1,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,1, %U A176890 1,1,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,1,0,0,0,0,0,0,0 %N A176890 Triangle T(n,k) read by rows. Signed subsequence of A051731. %C A176890 Let A=A176890*A176890, B=A*A, C=B*B, D=C*C and so on, then the leftmost column in the last matrix converges to the Moebius function A008683. %F A176890 T(n,k) = if n=1 and k=1 then -1 elseif n=k then 0 elseif k divides n then 1 else 0. %e A176890 Table begins: %e A176890 -1, %e A176890 1,0, %e A176890 1,0,0, %e A176890 1,1,0,0, %e A176890 1,0,0,0,0, %e A176890 1,1,1,0,0,0, %e A176890 1,0,0,0,0,0,0, %e A176890 1,1,0,1,0,0,0,0, %e A176890 1,0,1,0,0,0,0,0,0, %e A176890 1,1,0,0,1,0,0,0,0,0, %o A176890 (Excel) =if(and(row()=1;column()=1);-1;if(mod(row();column())=0;1;0)-if(and(column()>1;row()=column());1;0)) %Y A176890 Cf. A051731, A008683. %Y A176890 This is A176918 * the diagonalized mu(n). %K A176890 sign,tabl %O A176890 1,1 %A A176890 Mats Granvik and _Gary W. Adamson_, Apr 28 2010