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 A055135 #8 Apr 14 2017 03:01:08
%S A055135 1,0,1,-1,-2,1,-2,0,-6,1,-3,0,18,-12,1,-4,0,-40,80,-20,1,-5,0,75,-400,
%T A055135 225,-30,1,-6,0,-126,1680,-1890,504,-42,1,-7,0,196,-6272,13230,-6272,
%U A055135 980,-56,1,-8,0,-288,21504,-81648,64512,-16800,1728,-72,1,-9,0,405
%N A055135 Matrix inverse of triangle A055134.
%e A055135 1;
%e A055135 0,1;
%e A055135 -1,-2,1;
%e A055135 -2,0,-6,1;
%e A055135 -3,0,18,-12,1;
%e A055135 ...
%t A055135 rows = 12; row[n_] := Join[CoefficientList[(x+n-1)^n + O[x]^(n+1), x], Table[0, {rows-n-1}]]; M = Inverse[Table[row[n], {n, 0, rows-1}]]; Table[ M[[n+1, k+1]], {n, 0, rows-1}, {k, 0, n}] // Flatten (* _Jean-François Alcover_, Apr 14 2017 *)
%Y A055135 Cf. A055136.
%K A055135 sign,tabl
%O A055135 0,5
%A A055135 _Christian G. Bower_, Apr 25 2000