Real-rooted atlas

A120910 → Veronese 2 → x ↦ x+1

nonnegative coefficients

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

Recurrence

\(\left(-2 + 2\,n\right)\,P_{n}(x) = \left(-5 - x + 5\,n + n x\right)\,P_{n-1}(x) + \left(6 + 4\,x - 2\,x^{2}\right)\,P_{n-1}'(x)\)
\(P_{0}(x) = 3\)
\(P_{1}(x) = 6\)

Rows ?

nx0x1x2x3Pn(1)
033
166
215318
3421860
4123783204
536630030696
61095108918932376
732823822966428112

All 15 rows

Other recurrences

Image under the basis map A007318 · proved equal for all n (proof step)

\(P_{n}(x) = \left(-3 + x\right)\,P_{n-2}(x) + \left(4\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 3\)
\(P_{1}(x) = 6\)
Technical details
Node id
n-2ca20f5a0bd85ef7 · revision 0 · JSON
Definition source
derived:shift_x_plus_one
derived:basis_map_A007318 (equal by e-836f377f58171f68)
Fingerprint
f6-97ff5e3c0ee49bcd

Observed on the stored rows ?

  • Degrees: 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7 (half affine: slope 1, intercept 0)
  • 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:     3;
  1:     6;
  2:    15,     3;
  3:    42,    18;
  4:   123,    78,     3;
  5:   366,   300,    30;
  6:  1095,  1089,   189,    3;
  7:  3282,  3822,   966,   42;
  8:  9843, 13116,  4386,  348,  3;
  9: 29526, 44280, 18468, 2232, 54;
%F Formula
The row polynomials satisfy (2*n-2)*P(n,x) = (5*n-5+(n-1)*x)*P(n-1,x) + (6+4*x-2*x^2)*d/dx P(n-1,x) for n >= 2, with P(0,x) = 3, P(1,x) = 6.
%t Mathematica
P[0, x_] := 3;
P[1, x_] := 6;
P[n_, x_] := P[n, x] = Expand[Together[((5*n - 5 + (n - 1)*x)*P[n - 1, x] + (6 + 4*x - 2*x^2)*D[P[n - 1, x], x])/(2*n - 2)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 3; v[2] = 6; for(n = 2, N, my(i = n + 1); v[i] = ((5*n - 5 + (n - 1)*x)*v[i - 1] + (6 + 4*x - 2*x^2)*deriv(v[i - 1], x))/(2*n - 2)); 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. [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
  7. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.