A113953 → D+1

nonnegative coefficients

Proved for all n: all roots real, in (−∞, 0] · coefficients of one sign · Hadamard kernel what this means

Recurrence
\(\left(-11\,n x + 5\,n x^{2} + n x^{3} - 2\,n^{2} + 7\,n^{2} x + n^{2} x^{2} + 2\,n^{3}\right)\,P_{n}(x) = \left(-48\,x + 16\,x^{2} + 10\,x^{3} + x^{4} - 24\,n + 66\,n x - 10\,n x^{2} - 3\,n x^{3} + 32\,n^{2} - 22\,n^{2} x - 4\,n^{2} x^{2} - 8\,n^{3}\right)\,P_{n-1}(x) + \left(-32\,x^{2} + 52\,x^{3} + 15\,x^{4} + x^{5} - 16\,n x + 54\,n x^{2} + 15\,n x^{3} + n x^{4} + 16\,n^{2} x + 2\,n^{2} x^{2}\right)\,P_{n-1}'(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1112
22417
3087116
4082210141
500364413194
6002410474161219
7000128232112191492

Generated b-files: A073371 (row sums) ?

Computed in your browser ?

Technical details
Node id
n-d1ec595c61033c43 · revision 1 · JSON
Definition source
derived:one_plus_derivative
Fingerprint
f6-2450a51cfab3abfe

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 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

OEIS matches ?

A generated b-file is computed from the node's definition along the row alignment of its OEIS link and starts at the entry's offset. It is an identification on a finite prefix, not a proof that the node and the OEIS entry agree for every n.

OEIS submission text ?

Fields to paste into an OEIS submission: the example %e, the formula %F and programs %t (Mathematica) and %o (PARI/GP) that list the same rows. For an OEIS link the row numbers, the offset and the orientation are those of the entry, as matched; the matched terms were compared with the published ones, which identifies the node with the entry on a finite prefix, not for every n. The PARI/GP program is not machine-checked here.

The atlas's own rows: n = 0, …, ascending powers of x
%e Example
Triangle begins:
  0: 1;
  1: 1, 1;
  2: 2, 4,  1;
  3: 0, 8,  7,   1;
  4: 0, 8, 22,  10,   1;
  5: 0, 0, 36,  44,  13,    1;
  6: 0, 0, 24, 104,  74,   16,   1;
  7: 0, 0,  0, 128, 232,  112,  19,   1;
  8: 0, 0,  0,  64, 416,  440, 158,  22,  1;
  9: 0, 0,  0,   0, 400, 1040, 748, 212, 25, 1;
%F Formula
The row polynomials satisfy (2*n^3-2*n^2+(7*n^2-11*n)*x+(n^2+5*n)*x^2+n*x^3)*P(n,x) = -(8*n^3-32*n^2+24*n+(22*n^2-66*n+48)*x+(4*n^2+10*n-16)*x^2+(3*n-10)*x^3-x^4)*P(n-1,x) + ((16*n^2-16*n)*x+(2*n^2+54*n-32)*x^2+(15*n+52)*x^3+(n+15)*x^4+x^5)*d/dx P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[(-(8*n^3 - 32*n^2 + 24*n + (22*n^2 - 66*n + 48)*x + (4*n^2 + 10*n - 16)*x^2 + (3*n - 10)*x^3 - x^4)*P[n - 1, x] + ((16*n^2 - 16*n)*x + (2*n^2 + 54*n - 32)*x^2 + (15*n + 52)*x^3 + (n + 15)*x^4 + x^5)*D[P[n - 1, x], x])/(2*n^3 - 2*n^2 + (7*n^2 - 11*n)*x + (n^2 + 5*n)*x^2 + n*x^3)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = (-(8*n^3 - 32*n^2 + 24*n + (22*n^2 - 66*n + 48)*x + (4*n^2 + 10*n - 16)*x^2 + (3*n - 10)*x^3 - x^4)*v[i - 1] + ((16*n^2 - 16*n)*x + (2*n^2 + 54*n - 32)*x^2 + (15*n + 52)*x^3 + (n + 15)*x^4 + x^5)*deriv(v[i - 1], x))/(2*n^3 - 2*n^2 + (7*n^2 - 11*n)*x + (n^2 + 5*n)*x^2 + n*x^3)); 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)

Generated with polytool c48629374597.

Proved properties

  • Real-rooted. Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
    Every polynomial of the sequence has only real roots, inside the stated interval.
    by the cited steps: e-5e8f0cb9241868fa
  • Coefficients of one sign. Every nonzero row, n >= 0: the coefficients of P_n have one sign
    All coefficients of each polynomial have the same sign (after x -> -x when alternating).
    derived from the cited steps by a stated theorem: e-5e8f0cb9241868fa
  • Hadamard kernel (Malo). Rows P_n, n >= 0, are Hadamard kernels (preserve real-rootedness)
    Multiplying the coefficients of any real-rooted polynomial termwise by those of a row (Hadamard product) gives a real-rooted polynomial again.
    derived from the cited steps by a stated theorem: e-5e8f0cb9241868fa

Proof chains

1 incoming proof step. Each step is expanded back to the roots of the proof DAG, the theorem checks of a node's own rule. JSON

No candidate equalities or related sequences.

References

  1. [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
  2. [MW08] Shi-Mei Ma and Yi Wang. q-Eulerian polynomials and polynomials with only real zeros. The Electronic Journal of Combinatorics, 15(1):Research Paper 17, January 2008. doi:10.37236/741
  3. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.