Real-rooted atlas

A054142 → Veronese 2 (j=1) → x ↦ x+1

nonnegative coefficients

Proved for all n all roots real, in (−∞, −1]coefficients of one signHadamard kernel

Recurrence

\(P_{n}(x) = \left(-1 - 2\,x - x^{2}\right)\,P_{n-4}(x) + \left(2 + 2\,x\right)\,P_{n-3}(x) + \left(1 + 2\,x\right)\,P_{n-2}(x) + \left(2\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 1\)
\(P_{2}(x) = 3\)
\(P_{3}(x) = 6 + x\)

Rows ?

nx0x1x2x3x4x5x6Pn(1)
00
111
233
3617
4171027
54537183
611612621263
73054201291855
87991318570362723
920904023228333418731
10547312054848119365527999
111432935515297939305720189663
123751210334010078240248539578287355
13982092977043310381612983115013711920771
142571158504601062092611652155833130061052950263
Technical details
Node id
n-4017c63c30535842 · revision 0 · JSON
Definition source
derived:shift_x_plus_one
Fingerprint
f6-fad358f622a81bb9

Observed on the stored rows ?

  • Degrees: -1, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6 (half 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 = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:    0;
  1:    1;
  2:    3;
  3:    6,    1;
  4:   17,   10;
  5:   45,   37,    1;
  6:  116,  126,   21;
  7:  305,  420,  129,   1;
  8:  799, 1318,  570,  36;
  9: 2090, 4023, 2283, 334, 1;
%F Formula
The row polynomials satisfy P(n,x) = -(1+2*x+x^2)*P(n-4,x) + (2+2*x)*P(n-3,x) + (1+2*x)*P(n-2,x) + 2*P(n-1,x) for n >= 4, with P(0,x) = 0, P(1,x) = 1, P(2,x) = 3, P(3,x) = 6 + x.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 1;
P[2, x_] := 3;
P[3, x_] := 6 + x;
P[n_, x_] := P[n, x] = Expand[-(1 + 2*x + x^2)*P[n - 4, x] + (2 + 2*x)*P[n - 3, x] + (1 + 2*x)*P[n - 2, x] + 2*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 0; v[2] = 1; v[3] = 3; v[4] = 6 + x; for(n = 4, N, my(i = n + 1); v[i] = -(1 + 2*x + x^2)*v[i - 4] + (2 + 2*x)*v[i - 3] + (1 + 2*x)*v[i - 2] + 2*v[i - 1]); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i - 1, v[i])))};
T(9)

polytool c48629374597

Properties

Proof chains ? JSON

References

  1. [ASW52] Michael Aissen, I. J. Schoenberg and A. M. Whitney. On the generating functions of totally positive sequences I. Journal d’Analyse Mathématique, 2(1):93–103, 1952. doi:10.1007/BF02786970
  2. [AW24] Christos A. Athanasiadis and David G. Wagner. Veronese sections and interlacing matrices of polynomials and formal power series. arXiv:2404.12989. arXiv
  3. [Edr53] Albert Edrei. Proof of a Conjecture of Schoenberg on the Generating Function of a Totally Positive Sequence. Canadian Journal of Mathematics, 5:86–94, 1953. doi:10.4153/CJM-1953-010-3
  4. [Fav35] Jean Favard. Sur les polynômes de tchebicheff. C. R. Acad. Sci. Paris, 200:2052–2053, 1935.
  5. [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
  6. [Sze39] G. Szegő. Orthogonal Polynomials. Colloquium publications, American Mathematical Society, 1939. doi:10.1090/coll/023