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 A155091 #2 Mar 30 2012 18:53:09 %S A155091 1,-1,1,0,-1,1,0,-1,-1,1,0,0,-1,-1,1,0,0,-1,-1,-1,1,0,0,0,-1,-1,-1,1, %T A155091 0,0,0,-1,-1,-1,-1,1,0,0,0,0,-1,-1,-1,-1,1,0,0,0,0,-1,-1,-1,-1,-1,1,0, %U A155091 0,0,0,0,-1,-1,-1,-1,-1,1,0,0,0,0,0,-1,-1,-1,-1,-1,-1,1,0,0,0,0,0,0,-1,-1 %N A155091 Triangle read by rows. Signed version of A145362. Main diagonal positive, rest of the nonzero terms negative. %C A155091 Matrix inverse of this triangle is A155092. %e A155091 Table begins: %e A155091 1, %e A155091 -1,1, %e A155091 0,-1,1, %e A155091 0,-1,-1,1, %e A155091 0,0,-1,-1,1, %e A155091 0,0,-1,-1,-1,1, %e A155091 0,0,0,-1,-1,-1,1, %e A155091 0,0,0,-1,-1,-1,-1,1, %e A155091 0,0,0,0,-1,-1,-1,-1,1, %e A155091 0,0,0,0,-1,-1,-1,-1,-1,1, %Y A155091 Cf. A145362. %K A155091 sign,tabl %O A155091 1,1 %A A155091 _Mats Granvik_, Jan 20 2009