basis-map coefficients of A026729, shifted → θ+1 → D

palindromicγ-positiveonly rational roots

Proved for all n all roots real, in (−∞, 0]coefficients of one signHadamard kernel

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
10
2-2-2
3066
400-12-12
50002020
60000-30-30
7000004242
8000000-56-56
900000007272
1000000000-90-90
11000000000110110
120000000000-132-132
1300000000000156156
14000000000000-182-182
150000000000000210210
Technical details
Node id
n-22baeff6980f38d6 · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-edf6954a4cd8adfc

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: yes
  • γ-positive (gamma_positive): yes
  • Nonnegative coefficients (nonn): no
  • Only rational roots (rr_by_factors: every nonzero row is a product of linear factors over ℚ): yes

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:  0;
   2: -2;
   3:  0, 6;
   4:  0, 0, -12;
   5:  0, 0,   0, 20;
   6:  0, 0,   0,  0, -30;
   7:  0, 0,   0,  0,   0, 42;
   8:  0, 0,   0,  0,   0,  0, -56;
   9:  0, 0,   0,  0,   0,  0,   0, 72;
  10:  0, 0,   0,  0,   0,  0,   0,  0, -90;
%F Formula
The row polynomials satisfy (n-2)*P(n,x) = -n*x*P(n-1,x) for n >= 3, with P(1,x) = 0, P(2,x) = -2.
%t Mathematica
P[1, x_] := 0;
P[2, x_] := -2;
P[n_, x_] := P[n, x] = Expand[Together[(-n*x*P[n - 1, x])/(n - 2)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 0; v[2] = -2; for(n = 3, N, my(i = n); v[i] = (-n*x*v[i - 1])/(n - 2)); 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)

polytool c48629374597

Properties

Proof chains ? JSON

Same fingerprint ?

References

  1. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  2. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.