basis-map coefficients of A297191, shifted → (θ+1)² → θ+1

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-1 + 6\,n - 12\,n^{2} + 8\,n^{3}\right)\,P_{n}(x) = \left(x^{2} + 6\,n x^{2} + 12\,n^{2} x^{2} + 8\,n^{3} x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1002727
20000125125
3000000343343
400000000729729
5000000000013311331
600000000000021972197
70000000000000033753375
Technical details
Node id
n-73608580bc5459cb · revision 0 · JSON
Definition source
derived:theta_plus_one_squared
Fingerprint
f6-edf6954a4cd8adfc

Observed on the stored rows ?

  • Degrees: 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28 (affine: slope 2, intercept 0)
  • 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: 1;
  1: 0, 0, 27;
  2: 0, 0,  0, 0, 125;
  3: 0, 0,  0, 0,   0, 0, 343;
  4: 0, 0,  0, 0,   0, 0,   0, 0, 729;
  5: 0, 0,  0, 0,   0, 0,   0, 0,   0, 0, 1331;
  6: 0, 0,  0, 0,   0, 0,   0, 0,   0, 0,    0, 0, 2197;
  7: 0, 0,  0, 0,   0, 0,   0, 0,   0, 0,    0, 0,    0, 0, 3375;
  8: 0, 0,  0, 0,   0, 0,   0, 0,   0, 0,    0, 0,    0, 0,    0, 0, 4913;
  9: 0, 0,  0, 0,   0, 0,   0, 0,   0, 0,    0, 0,    0, 0,    0, 0,    0, 0, 6859;
%F Formula
The row polynomials satisfy (8*n^3-12*n^2+6*n-1)*P(n,x) = (8*n^3+12*n^2+6*n+1)*x^2*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((8*n^3 + 12*n^2 + 6*n + 1)*x^2*P[n - 1, x])/(8*n^3 - 12*n^2 + 6*n - 1)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = ((8*n^3 + 12*n^2 + 6*n + 1)*x^2*v[i - 1])/(8*n^3 - 12*n^2 + 6*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.