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 A136481 #9 Feb 18 2024 09:05:32
%S A136481 1,1,-1,-1,-2,1,1,0,3,-1,-1,0,2,-4,1,1,0,0,-5,5,-1,-1,0,0,-2,9,-6,1,1,
%T A136481 0,0,0,7,-14,7,-1,-1,0,0,0,2,-16,20,-8,1,1,0,0,0,0,-9,30,-27,9,-1,-1,
%U A136481 0,0,0,0,-2,25,-50,35,-10,1
%N A136481 Triangle: h(n,m)=If[m == 1, n, If[n - m + 1 == 0, 1, If[n - m == 0, 1, If[n - m > 0, 1, 0]]]],n,m<=d.
%e A136481 {1},
%e A136481 {1, -1},
%e A136481 {-1, -2, 1},
%e A136481 {1, 0, 3, -1},
%e A136481 {-1, 0, 2, -4, 1},
%e A136481 {1, 0, 0, -5, 5, -1},
%e A136481 {-1, 0, 0, -2, 9, -6, 1},
%e A136481 {1, 0, 0, 0, 7, -14, 7, -1},
%e A136481 {-1,0, 0, 0, 2, -16, 20, -8, 1},
%e A136481 {1, 0, 0, 0, 0, -9, 30, -27,9, -1},
%e A136481 {-1, 0, 0, 0, 0, -2, 25, -50, 35, -10, 1}
%t A136481 f[n_, m_] := If[m == 1, n,If[n - m + 1 == 0, 1, If[n - m == 0, 1, If[n - m > 0, 1, 0]]]];
%t A136481 M[d_] := Table[Table[f[n, m], {n, 1, d}], {m, 1, d}];
%t A136481 a = Join[{{1}}, Table[CoefficientList[CharacteristicPolynomial[M[n], x], x], {n, 1, 10}]];
%t A136481 Flatten[a]
%K A136481 uned,tabl,sign,less
%O A136481 1,5
%A A136481 _Roger L. Bagula_, Mar 20 2008