basis-map coefficients of A297191, shifted → D

palindromic γ-positive nonnegative coefficients only rational roots

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

Recurrence
\(\left(-1 + n\right)\,P_{n}(x) = \left(n x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 2\,x\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
1022
200044
30000066
4000000088
50000000001010
6000000000001212
700000000000001414

Generated b-files: A005843 (row sums) ?

Computed in your browser ?

Technical details
Node id
n-e75bc09e82ca4254 · revision 1 · JSON
Definition source
derived:derivative
Fingerprint
f6-edf6954a4cd8adfc

Observed on the stored rows ?

  • Degrees: -1, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27 (affine: slope 2, intercept -1)
  • Palindromic rows: yes
  • γ-positive (gamma_positive): yes
  • 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: 0, 2;
  2: 0, 0, 0, 4;
  3: 0, 0, 0, 0, 0, 6;
  4: 0, 0, 0, 0, 0, 0, 0, 8;
  5: 0, 0, 0, 0, 0, 0, 0, 0, 0, 10;
  6: 0, 0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 12;
  7: 0, 0, 0, 0, 0, 0, 0, 0, 0,  0, 0,  0, 0, 14;
  8: 0, 0, 0, 0, 0, 0, 0, 0, 0,  0, 0,  0, 0,  0, 0, 16;
  9: 0, 0, 0, 0, 0, 0, 0, 0, 0,  0, 0,  0, 0,  0, 0,  0, 0, 18;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = n*x^2*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 2*x.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 2*x;
P[n_, x_] := P[n, x] = Expand[Together[(n*x^2*P[n - 1, x])/(n - 1)]];
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] = 2*x; for(n = 2, N, my(i = n + 1); v[i] = (n*x^2*v[i - 1])/(n - 1)); 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-521a2a476289c028
  • 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-521a2a476289c028
  • 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-521a2a476289c028

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

Same fingerprint (75)

Equal up to content, sign, reversal and a small index shift.

References

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