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 A178408 #4 Aug 10 2015 00:38:28 %S A178408 1,0,-1,0,-1,0,0,-1,1,0,0,-1,0,0,0,0,-1,2,0,0,0,0,-1,0,0,0,0,0,0,-1,2, %T A178408 -1,0,0,0,0,0,-1,1,0,0,0,0,0,0,0,-1,2,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0, %U A178408 0,0,0,0,-1,4,-3,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,-1,2,0,0,0 %N A178408 Triangle T(n,k) read by rows. Each column is the Mobius function "recurrence" with the previous column as input. %C A178408 The title says "recurrence" in quotes because the Mobius function does not have a regular recurrence. Row sums are A008683. Number of nonzero elements in the rows are A086436 which is essentially the same as A001222. Each row is a row in a Pascal like triangle. %e A178408 Table begins: %e A178408 1, %e A178408 0,-1, %e A178408 0,-1,0, %e A178408 0,-1,1,0, %e A178408 0,-1,0,0,0, %e A178408 0,-1,2,0,0,0, %e A178408 0,-1,0,0,0,0,0, %e A178408 0,-1,2,-1,0,0,0,0, %e A178408 0,-1,1,0,0,0,0,0,0, %e A178408 0,-1,2,0,0,0,0,0,0,0, %Y A178408 Cf. A008683, A086436, A001222. %K A178408 sign,tabl %O A178408 1,18 %A A178408 _Mats Granvik_, May 27 2010