A099097 → D

nonnegative coefficients

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

Recurrence
\(\left(6 + 54\,x - 9\,n - 27\,n x + 3\,n^{2}\right)\,P_{n}(x) = \left(-16 - 108\,x - 162\,x^{2} + 12\,n + 45\,n x - 2\,n^{2}\right)\,P_{n-1}(x) + \left(-8\,x - 54\,x^{2} - 81\,x^{3} + 4\,n x + 9\,n x^{2}\right)\,P_{n-1}'(x)\)
\(P_{1}(x) = 0\)
\(P_{2}(x) = 3\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
10
233
311819
40128193
50281324407
6002743212151674
7003216202543746618
800048135087481530925455
900044507290357215248895953
10000075324035721139968177147356151
1100005810198451632965314415904901305887
12000001086615108864708588196830019486174741092
1300000613234536055112429524507144929637729217072484
1400000014712096275562262440011908215255091682072619961055787
150000007201691854153090011908215467668088981352966961566217074895

Computed in your browser ?

Technical details
Node id
n-4634927692f4f2c9 · revision 1 · JSON
Definition source
derived:derivative
Fingerprint
f6-2e4970c7c29b11f6

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 -2)
  • 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 ?

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 = 1, …, ascending powers of x
%e Example
Triangle begins:
   1: 0;
   2: 3;
   3: 1, 18;
   4: 0, 12, 81;
   5: 0,  2, 81, 324;
   6: 0,  0, 27, 432, 1215;
   7: 0,  0,  3, 216, 2025, 4374;
   8: 0,  0,  0,  48, 1350, 8748, 15309;
   9: 0,  0,  0,   4,  450, 7290, 35721,  52488;
  10: 0,  0,  0,   0,   75, 3240, 35721, 139968, 177147;
%F Formula
The row polynomials satisfy (3*n^2-9*n+6-(27*n-54)*x)*P(n,x) = -(2*n^2-12*n+16-(45*n-108)*x+162*x^2)*P(n-1,x) + ((4*n-8)*x+(9*n-54)*x^2-81*x^3)*d/dx P(n-1,x) for n >= 3, with P(1,x) = 0, P(2,x) = 3.
%t Mathematica
P[1, x_] := 0;
P[2, x_] := 3;
P[n_, x_] := P[n, x] = Expand[Together[(-(2*n^2 - 12*n + 16 - (45*n - 108)*x + 162*x^2)*P[n - 1, x] + ((4*n - 8)*x + (9*n - 54)*x^2 - 81*x^3)*D[P[n - 1, x], x])/(3*n^2 - 9*n + 6 - (27*n - 54)*x)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 0; v[2] = 3; for(n = 3, N, my(i = n); v[i] = (-(2*n^2 - 12*n + 16 - (45*n - 108)*x + 162*x^2)*v[i - 1] + ((4*n - 8)*x + (9*n - 54)*x^2 - 81*x^3)*deriv(v[i - 1], x))/(3*n^2 - 9*n + 6 - (27*n - 54)*x)); 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)

Generated with polytool c48629374597.

Proved properties

  • Real-rooted. Every row P_n, n >= 1, 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-ab48d0fc2b7fbb7d
  • Coefficients of one sign. Every nonzero row, n >= 1: 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-ab48d0fc2b7fbb7d
  • Hadamard kernel (Malo). Rows P_n, n >= 1, 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-ab48d0fc2b7fbb7d

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. [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
  2. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.