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 A328649 #12 Dec 10 2023 17:45:43 %S A328649 2,-1,-1,-4,1,3,3,6,-1,-4,-12,-6,-8,1,7,20,30,10,10,-1,-11,-42,-60, %T A328649 -60,-15,-12,1,18,77,147,140,105,21,14,-1,-29,-144,-308,-392,-280, %U A328649 -168,-28,-16,1,47,261,648,924,882,504,252,36,18,-1,-76,-470,-1305 %N A328649 Irregular triangular array read by rows: row n shows the coefficients of the following polynomial of degree n: (1/n!)*(numerator of n-th derivative of (x-2)/(1-x-x^2)). %C A328649 The first 201 polynomials are irreducible. Column 1: signed Lucas numbers (A000032). %e A328649 First eight rows: %e A328649 2, -1; %e A328649 -1, -4, 1; %e A328649 3, 3, 6, -1; %e A328649 -4, -12, -6, -8, 1; %e A328649 7, 20, 30, 10, 10, -1; %e A328649 -11, -42, -60, -60, -15, -12, 1; %e A328649 18, 77, 147, 140, 105, 21, 14, -1; %e A328649 -29, -144, -308, -392, -280, -168, -28, -16, 1; %e A328649 First eight polynomials: %e A328649 2 - x %e A328649 -1 - 4 x + x^2 %e A328649 3 + 3 x + 6 x^2 - x^3 %e A328649 -4 - 12 x - 6 x^2 - 8 x^3 + x^4 %e A328649 7 + 20 x + 30 x^2 + 10 x^3 + 10 x^4 - x^5 %e A328649 -11 - 42 x - 60 x^2 - 60 x^3 - 15 x^4 - 12 x^5 + x^6 %e A328649 18 + 77 x + 147 x^2 + 140 x^3 + 105 x^4 + 21 x^5 + 14 x^6 - x^7 %e A328649 -29 - 144 x - 308 x^2 - 392 x^3 - 280 x^4 - 168 x^5 - 28 x^6 - 16 x^7 + x^8 %t A328649 g[x_, n_] := Numerator[ Factor[D[(x - 2)/(1 - x - x^2), {x, n}]]] %t A328649 Column[Expand[Table[g[x, n]/n!, {n, 0, 12}]]] (* A328649 polynomials *) %t A328649 h[n_] := CoefficientList[g[x, n]/n!, x]; %t A328649 Table[h[n], {n, 0, 10}] (* A328649 sequence *) %t A328649 Column[%] (* A328649 array *) %Y A328649 Cf. A000032, A328646. %K A328649 tabf,sign %O A328649 0,1 %A A328649 _Clark Kimberling_, Nov 01 2019