Real-rooted atlas

A111125 → basis A013609 → reverse

nonnegative coefficients

Proved for all n all roots real, in (−∞, 0]coefficients of one signHadamard kernel

Recurrence

\(\left(-6 + 4\,n\right)\,P_{n}(x) = \left(-12 - 28\,x - 10\,x^{2} + 8\,n + 18\,n x + 5\,n x^{2}\right)\,P_{n-1}(x) + \left(-4\,x - 12\,x^{2} - 5\,x^{3}\right)\,P_{n-1}'(x)\)
\(P_{1}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
111
2246
34141129
48406229139
51610424023076666
63225678411407801993191
764608232045284740250852115289
8128140864321576022280180967786136473254

All 15 rows

Technical details
Node id
n-74c5a3a593f6b651 · revision 0 · JSON
Definition source
derived:reversal
Fingerprint
f6-c933affcacfcef22

Observed on the stored rows ?

  • Degrees: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 (affine: slope 1, intercept -1)
  • Palindromic rows: no
  • γ-positive (gamma_positive): no
  • Nonnegative coefficients (nonn): yes
  • Only rational roots (rr_by_factors: every nonzero row is a product of linear factors over ℚ): no

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:   1;
   2:   2,    4;
   3:   4,   14,    11;
   4:   8,   40,    62,     29;
   5:  16,  104,   240,    230,     76;
   6:  32,  256,   784,   1140,    780,    199;
   7:  64,  608,  2320,   4528,   4740,   2508,    521;
   8: 128, 1408,  6432,  15760,  22280,  18096,   7786,   1364;
   9: 256, 3200, 17024,  50208,  89520,  98504,  65120,  23578,  3571;
  10: 512, 7168, 43520, 150080, 323232, 449808, 403472, 224420, 70090, 9349;
%F Formula
The row polynomials satisfy (4*n-6)*P(n,x) = (8*n-12+(18*n-28)*x+(5*n-10)*x^2)*P(n-1,x) - (4*x+12*x^2+5*x^3)*d/dx P(n-1,x) for n >= 2, with P(1,x) = 1.
%t Mathematica
P[1, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((8*n - 12 + (18*n - 28)*x + (5*n - 10)*x^2)*P[n - 1, x] - (4*x + 12*x^2 + 5*x^3)*D[P[n - 1, x], x])/(4*n - 6)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 1; for(n = 2, N, my(i = n); v[i] = ((8*n - 12 + (18*n - 28)*x + (5*n - 10)*x^2)*v[i - 1] - (4*x + 12*x^2 + 5*x^3)*deriv(v[i - 1], x))/(4*n - 6)); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i, v[i])))};
T(10)

polytool c48629374597

Properties

Proof chains ? JSON

Same fingerprint ?

References

  1. [Fav35] Jean Favard. Sur les polynômes de tchebicheff. C. R. Acad. Sci. Paris, 200:2052–2053, 1935.
  2. [LW07] Lily L. Liu and Yi Wang. A unified approach to polynomial sequences with only real zeros. Advances in Applied Mathematics, 38(4):542–560, May 2007. doi:10.1016/j.aam.2006.02.003
  3. [Sze39] G. Szegő. Orthogonal Polynomials. Colloquium publications, American Mathematical Society, 1939. doi:10.1090/coll/023