basis-map coefficients of A297191, shifted → θ+1 → D

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

\(\left(1 - 3\,n + 2\,n^{2}\right)\,P_{n}(x) = \left(n x^{2} + 2\,n^{2} x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 6\,x\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14x15x16x17x18x19x20x21x22x23x24x25x26x27Pn(1)
00
1066
20002020
3000004242
400000007272
5000000000110110
600000000000156156
70000000000000210210
8000000000000000272272
900000000000000000342342
100000000000000000000420420
11000000000000000000000506506
1200000000000000000000000600600
130000000000000000000000000702702
14000000000000000000000000000812812
Technical details
Node id
n-9d26a1d9f476e370 · revision 0 · 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

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 0, …, ascending powers of x
%e Example
Triangle begins:
  0: 0;
  1: 0, 6;
  2: 0, 0, 0, 20;
  3: 0, 0, 0,  0, 0, 42;
  4: 0, 0, 0,  0, 0,  0, 0, 72;
  5: 0, 0, 0,  0, 0,  0, 0,  0, 0, 110;
  6: 0, 0, 0,  0, 0,  0, 0,  0, 0,   0, 0, 156;
  7: 0, 0, 0,  0, 0,  0, 0,  0, 0,   0, 0,   0, 0, 210;
  8: 0, 0, 0,  0, 0,  0, 0,  0, 0,   0, 0,   0, 0,   0, 0, 272;
  9: 0, 0, 0,  0, 0,  0, 0,  0, 0,   0, 0,   0, 0,   0, 0,   0, 0, 342;
%F Formula
The row polynomials satisfy (2*n^2-3*n+1)*P(n,x) = (2*n^2+n)*x^2*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 6*x.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 6*x;
P[n_, x_] := P[n, x] = Expand[Together[((2*n^2 + n)*x^2*P[n - 1, x])/(2*n^2 - 3*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] = 6*x; for(n = 2, N, my(i = n + 1); v[i] = ((2*n^2 + n)*x^2*v[i - 1])/(2*n^2 - 3*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)

polytool c48629374597

Properties

Proof chains ? JSON

Same fingerprint ?

References

  1. [Bra06] Petter Brändén. On linear transformations preserving the Pólya frequency property. Transactions of the American Mathematical Society, 358(8):3697–3716, February 2006. doi:10.1090/s0002-9947-06-03856-6
  2. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  3. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.