A103633 → D

nonnegative coefficients only rational roots

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

Recurrence
\(\left(6\,x + 8\,x^{2} - n - 10\,n x - 12\,n x^{2} + n^{2} + 4\,n^{2} x + 4\,n^{2} x^{2}\right)\,P_{n}(x) = \left(8\,x^{3} - 3\,n - 19\,n x - 46\,n x^{2} - 44\,n x^{3} + 4\,n^{2} + 23\,n^{2} x + 48\,n^{2} x^{2} + 36\,n^{2} x^{3} - n^{3} - 6\,n^{3} x - 12\,n^{3} x^{2} - 8\,n^{3} x^{3}\right)\,P_{n-1}(x) + \left(4\,x^{3} + 4\,x^{4} - 2\,n x - 14\,n x^{2} - 28\,n x^{3} - 16\,n x^{4} + 2\,n^{2} x + 10\,n^{2} x^{2} + 16\,n^{2} x^{3} + 8\,n^{2} x^{4}\right)\,P_{n-1}'(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6Pn(1)
00
111
2123
30235
4026412
50038516
60031215636
700041518744

Generated b-files: A203150 (row sums) ?

Computed in your browser ?

Technical details
Node id
n-8d06c768dd7b6bf3 · revision 1 · JSON
Definition source
derived:derivative
Fingerprint
f6-fa800db18f277715

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

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: 0;
  1: 1;
  2: 1, 2;
  3: 0, 2, 3;
  4: 0, 2, 6,  4;
  5: 0, 0, 3,  8,  5;
  6: 0, 0, 3, 12, 15,  6;
  7: 0, 0, 0,  4, 15, 18,  7;
  8: 0, 0, 0,  4, 20, 36, 28,  8;
  9: 0, 0, 0,  0,  5, 24, 42, 32, 9;
%F Formula
The row polynomials satisfy (n^2-n+(4*n^2-10*n+6)*x+(4*n^2-12*n+8)*x^2)*P(n,x) = -(n^3-4*n^2+3*n+(6*n^3-23*n^2+19*n)*x+(12*n^3-48*n^2+46*n)*x^2+(8*n^3-36*n^2+44*n-8)*x^3)*P(n-1,x) + ((2*n^2-2*n)*x+(10*n^2-14*n)*x^2+(16*n^2-28*n+4)*x^3+(8*n^2-16*n+4)*x^4)*d/dx P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 1.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[(-(n^3 - 4*n^2 + 3*n + (6*n^3 - 23*n^2 + 19*n)*x + (12*n^3 - 48*n^2 + 46*n)*x^2 + (8*n^3 - 36*n^2 + 44*n - 8)*x^3)*P[n - 1, x] + ((2*n^2 - 2*n)*x + (10*n^2 - 14*n)*x^2 + (16*n^2 - 28*n + 4)*x^3 + (8*n^2 - 16*n + 4)*x^4)*D[P[n - 1, x], x])/(n^2 - n + (4*n^2 - 10*n + 6)*x + (4*n^2 - 12*n + 8)*x^2)]];
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; for(n = 2, N, my(i = n + 1); v[i] = (-(n^3 - 4*n^2 + 3*n + (6*n^3 - 23*n^2 + 19*n)*x + (12*n^3 - 48*n^2 + 46*n)*x^2 + (8*n^3 - 36*n^2 + 44*n - 8)*x^3)*v[i - 1] + ((2*n^2 - 2*n)*x + (10*n^2 - 14*n)*x^2 + (16*n^2 - 28*n + 4)*x^3 + (8*n^2 - 16*n + 4)*x^4)*deriv(v[i - 1], x))/(n^2 - n + (4*n^2 - 10*n + 6)*x + (4*n^2 - 12*n + 8)*x^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)

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-a139b2269602238f
  • 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-a139b2269602238f
  • 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-a139b2269602238f

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