Real-rooted atlas

A132440 → θ+1 → D+1

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(4 - 12\,n + 13\,n^{2} - 6\,n^{3} + n^{4}\right)\,P_{n}(x) = \left(-n^{2} x^{2} + 2\,n^{3} x^{2} - n^{4} x^{2}\right)\,P_{n-2}(x) + \left(8\,n^{2} x - 8\,n^{3} x + 2\,n^{4} x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 1\)
\(P_{2}(x) = 4 + 4\,x\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
111
2448
3018927
400481664
500010025125
6000018036216
70000029449343
800000044864512
9000000064881729
10000000009001001000
1100000000012101211331
12000000000015841441728
130000000000020281692197
1400000000000025481962744
Technical details
Node id
n-180e8c7ade26d4e8 · revision 0 · JSON
Definition source
derived:one_plus_derivative
Fingerprint
f6-2327141074f67bdf

Observed on the stored rows ?

  • Degrees: -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 (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): yes

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 0, …, ascending powers of x
%e Example
Triangle begins:
  0: 0;
  1: 1;
  2: 4,  4;
  3: 0, 18,  9;
  4: 0,  0, 48,  16;
  5: 0,  0,  0, 100,  25;
  6: 0,  0,  0,   0, 180,  36;
  7: 0,  0,  0,   0,   0, 294,  49;
  8: 0,  0,  0,   0,   0,   0, 448,  64;
  9: 0,  0,  0,   0,   0,   0,   0, 648, 81;
%F Formula
The row polynomials satisfy (n^4-6*n^3+13*n^2-12*n+4)*P(n,x) = -(n^4-2*n^3+n^2)*x^2*P(n-2,x) + (2*n^4-8*n^3+8*n^2)*x*P(n-1,x) for n >= 3, with P(0,x) = 0, P(1,x) = 1, P(2,x) = 4 + 4*x.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 1;
P[2, x_] := 4 + 4*x;
P[n_, x_] := P[n, x] = Expand[Together[(-(n^4 - 2*n^3 + n^2)*x^2*P[n - 2, x] + (2*n^4 - 8*n^3 + 8*n^2)*x*P[n - 1, x])/(n^4 - 6*n^3 + 13*n^2 - 12*n + 4)]];
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] = 4 + 4*x; for(n = 3, N, my(i = n + 1); v[i] = (-(n^4 - 2*n^3 + n^2)*x^2*v[i - 2] + (2*n^4 - 8*n^3 + 8*n^2)*x*v[i - 1])/(n^4 - 6*n^3 + 13*n^2 - 12*n + 4)); 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

Same fingerprint ?

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. [Bra06] Petter Brändén. On linear transformations preserving the Pólya frequency property. Transactions of the American Mathematical Society, 358(8):3697–3716, February 2006. doi:10.1090/s0002-9947-06-03856-6
  4. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  5. [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
  6. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.