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 A122771 #38 Jun 12 2021 02:45:47
%S A122771 1,2,-1,-1,-1,1,2,-2,2,-1,-1,-2,4,-3,1,2,-3,6,-7,4,-1,-1,-3,9,-13,11,
%T A122771 -5,1,2,-4,12,-22,24,-16,6,-1,-1,-4,16,-34,46,-40,22,-7,1,2,-5,20,-50,
%U A122771 80,-86,62,-29,8,-1,-1,-5,25,-70,130,-166,148,-91,37,-9,1,2,-6,30,-95,200,-296,314,-239,128,-46,10,-1,-1,-6,36,-125
%N A122771 Triangle read by rows, 0 <= k <= n: T(n,k) is the coefficient of x^k in the characteristic polynomial of I + A^(-1), where A is the n-step Fibonacci companion matrix and I is the identity matrix.
%C A122771 Here, the characteristic polynomial of a matrix M is defined as det(M-x*I).
%C A122771 The matrix I + A^(-1) for 2 <= n <= 6:
%C A122771 2 X 2: {{0, 1}, {1, 1}},
%C A122771 3 X 3: {{0, -1, 1}, {1, 1, 0}, {0, 1, 1}},
%C A122771 4 X 4: {{0, -1, -1, 1}, {1, 1, 0, 0}, {0, 1, 1, 0}, {0, 0, 1,1}},
%C A122771 5 X 5: {{0, -1, -1, -1, 1}, {1, 1, 0, 0, 0}, {0, 1, 1, 0, 0}, {0, 0, 1, 1, 0}, {0, 0, 0, 1,1}},
%C A122771 6 X 6: {{0, -1, -1, -1, -1, 1}, {1, 1, 0, 0, 0, 0}, {0, 1, 1, 0, 0, 0}, {0, 0, 1, 1, 0, 0}, {0, 0, 0, 1, 1, 0}, {0, 0, 0, 0, 1, 1}}
%D A122771 Jay Kappraff, Beyond Measure, A Guided Tour Through Nature, Myth and Number, World Scientific, 2002.
%D A122771 Kappraff, J., Blackmore, D. and Adamson, G. "Phyllotaxis as a Dynamical System: A Study in Number." In Symmetry in Plants edited by R. V. Jean and D. Barabe. Singapore: World Scientific. (1996).
%H A122771 P. Steinbach, <a href="https://www.jstor.org/stable/2691048">Golden fields: a case for the heptagon</a>, Math. Mag. 70 (1997), no. 1, 22-31.
%e A122771 Triangular array:
%e A122771 1;
%e A122771 2, -1;
%e A122771 -1, -1, 1;
%e A122771 2, -2, 2, -1;
%e A122771 -1, -2, 4, -3, 1;
%e A122771 2, -3, 6, -7, 4, -1;
%e A122771 -1, -3, 9, -13, 11, -5, 1;
%e A122771 2, -4, 12, -22, 24, -16, 6, -1;
%e A122771 -1, -4, 16, -34, 46, -40, 22, -7, 1;
%e A122771 2, -5, 20, -50, 80, -86, 62, -29, 8, -1;
%t A122771 An[d_] := Table[If[n == d, 1, If[m == n + 1, 1, 0]], {n, 1, d}, {m, 1, d}];
%t A122771 Join[{{1}}, Table[CoefficientList[CharacteristicPolynomial[IdentityMatrix[d] + MatrixPower[An[d], -1], x], x], {d, 1, 20}]];
%t A122771 Flatten[%]
%o A122771 (Python)
%o A122771 from sympy import Matrix,eye
%o A122771 def A122771_row(n):
%o A122771 if n==0: return [1]
%o A122771 A=Matrix(n,n,lambda i,j:int(i==n-1 or i==j-1))
%o A122771 p=(eye(n)+A.inv()).charpoly()
%o A122771 return [(-1)**n*c for c in p.all_coeffs()[::-1]] # _Pontus von Brömssen_, May 01 2021
%K A122771 tabl,sign
%O A122771 0,2
%A A122771 _Gary W. Adamson_ and _Roger L. Bagula_, Oct 20 2006
%E A122771 Edited by _Pontus von Brömssen_, May 01 2021