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 A334432 #11 Jun 19 2020 11:25:08
%S A334432 -4,1,-1,1,1,-3,1,-1,6,-5,1,-1,9,-6,1,-1,15,-35,28,-9,1,1,-21,70,-84,
%T A334432 45,-11,1,1,-24,26,-9,1,1,-36,210,-462,495,-286,91,-15,1,-1,45,-330,
%U A334432 924,-1287,1001,-455,120,-17,1,1,-48,148,-146,64,-13,1
%N A334432 Irregular triangle read by rows: T(m,k) gives the coefficients of x^k of the minimal polynomials of (2*cos(Pi/(2*m+1)))^2 = rho(2*n+1)^2, for m >= 0.
%C A334432 The length of row m is delta(2*m+1) + 1 = A055034(2*m+1) + 1.
%C A334432 For details see A334429, where the formula for the minimal polynomial MPc2(m, x) of 2*cos(Pi/(2*m+1))^2 = rho(2*m+1)^2, for m >= 0, is given.
%C A334432 The companion triangle for even n is A334431.
%F A334432 T(m, k) = [x^k] MPc2odd(m, x), with MPc2odd(m, x) = Product_{j=1..delta(2*m+1)} (x - (2 + R(rpnodd(2*m+1)_j, rho(2*m+1)))) (evaluated using C(2*m+1, rho(2*m+1)) = 0), for m >= 1, and MPc2odd(0, x) = -4 + x. Here R(n, x) is the monic Chebyshev R polynomial with coefficients given in A127672. C(n, x) is the minimal polynomial of rho(n) = 2*cos(Pi/n) given in A187360, and rpnodd(m) is the list of positive odd numbers coprime to 2*m + 1 and <= 2*m - 1.
%e A334432 The irregular triangle T(m,k) begins:
%e A334432 m, n \ k 0 1 2 3 4 5 6 7 8 9 ...
%e A334432 --------------------------------------------------------------
%e A334432 0, 1 -4 1
%e A334432 1, 3: -1 1
%e A334432 2, 5: 1 -3 1
%e A334432 3, 7: -1 6 -5 1
%e A334432 4, 9: -1 9 -6 1
%e A334432 5, 11: -1 15 -35 28 -9 1
%e A334432 6, 13: 1 -21 70 -84 45 -11 1
%e A334432 7, 15: 1 -24 26 -9 1
%e A334432 8, 17: 1 -36 210 -462 495 -286 91 -15 1
%e A334432 9, 19: -1 45 -330 924 -1287 1001 -455 120 -17 1
%e A334432 10, 21: 1 -48 148 -146 64 -13 1
%e A334432 ...
%Y A334432 Cf. A055034, A334429, A334431.
%K A334432 sign,tabf,easy
%O A334432 0,1
%A A334432 _Wolfdieter Lang_, Jun 15 2020