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 A328647 #9 Jun 04 2022 22:03:41 %S A328647 1,1,4,-2,-1,11,-12,3,1,29,-44,24,-4,-1,76,-145,110,-40,5,1,199,-456, %T A328647 435,-220,60,-6,-1,521,-1393,1596,-1015,385,-84,7,1,1364,-4168,5572, %U A328647 -4256,2030,-616,112,-8,-1,3571,-12276,18756,-16716,9576,-3654,924,-144 %N A328647 Irregular triangular array read by rows: row n shows the coefficients of this polynomial of degree n: (1/n!)*(numerator of n-th derivative of (1+x)/(x^2-3x+1)). %C A328647 The first 201 polynomials are irreducible. Column 1 of the array: A002879 (odd-indexed Lucas numbers). Row sums: A000032 (Lucas numbers). Alternating row sums: essentially 5*A030191. %e A328647 First eight rows: %e A328647 1, 1; %e A328647 4, -2, -1; %e A328647 11, -12, 3, 1; %e A328647 29, -44, 24, -4, -1; %e A328647 76, -145, 110, -40, 5, 1; %e A328647 199, -456, 435, -220, 60, -6, -1; %e A328647 521, -1393, 1596, -1015, 385, -84, 7, 1; %e A328647 1364, -4168, 5572, -4256, 2030, -616, 112, -8, -1; %e A328647 First eight polynomials: %e A328647 1 + x %e A328647 4 - 2 x - x^2 %e A328647 11 - 12 x + 3 x^2 + x^3 %e A328647 29 - 44 x + 24 x^2 - 4 x^3 - x^4 %e A328647 76 - 145 x + 110 x^2 - 40 x^3 + 5 x^4 + x^5 %e A328647 199 - 456 x + 435 x^2 - 220 x^3 + 60 x^4 - 6 x^5 - x^6 %e A328647 521 - 1393 x + 1596 x^2 - 1015 x^3 + 385 x^4 - 84 x^5 + 7 x^6 + x^7 %e A328647 1364 - 4168 x + 5572 x^2 - 4256 x^3 + 2030 x^4 - 616 x^5 + 112 x^6 - 8 x^7 - x^8 %t A328647 g[x_, n_] := Numerator[ Factor[D[(1 + x)/(x^2 - 3 x + 1), {x, n}]]] %t A328647 Column[Expand[Table[g[x, n]/n!, {n, 0, 12}]]] (* polynomials *) %t A328647 h[n_] := CoefficientList[g[x, n]/n!, x] %t A328647 Table[h[n], {n, 0, 10}] %t A328647 Column[%] (* A328647 array *) %Y A328647 Cf. A328646, A002879, A000032. %K A328647 tabf,sign %O A328647 0,3 %A A328647 _Clark Kimberling_, Nov 01 2019