basis-map coefficients of A021012 → Veronese 2 → (θ+1)²

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
111
20
3088
40
500216216
60
70001152011520
80
9000010080001008000
100
1100000130636800130636800
120
130000002347107840023471078400
140
15000000055794106368005579410636800
Technical details
Node id
n-0c15de6501cce9b2 · revision 0 · JSON
Definition source
derived:theta_plus_one_squared
Fingerprint
f6-1641c37dbfc60bc3

Observed on the stored rows ?

  • Degrees: 0, -1, 1, -1, 2, -1, 3, -1, 4, -1, 5, -1, 6, -1, 7 (half affine: slope 1, 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 = 1, …, ascending powers of x
%e Example
Triangle begins:
   1: 1;
   2: 0;
   3: 0, 8;
   4: 0;
   5: 0, 0, 216;
   6: 0;
   7: 0, 0,   0, 11520;
   8: 0;
   9: 0, 0,   0,     0, 1008000;
  10: 0;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = (n^3-3*n-2)*x*P(n-2,x) for n >= 3, with P(1,x) = 1, P(2,x) = 0.
%t Mathematica
P[1, x_] := 1;
P[2, x_] := 0;
P[n_, x_] := P[n, x] = Expand[Together[((n^3 - 3*n - 2)*x*P[n - 2, x])/(n - 1)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 1; v[2] = 0; for(n = 3, N, my(i = n); v[i] = ((n^3 - 3*n - 2)*x*v[i - 2])/(n - 1)); 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. [ASW52] Michael Aissen, I. J. Schoenberg and A. M. Whitney. On the generating functions of totally positive sequences I. Journal d’Analyse Mathématique, 2(1):93–103, 1952. doi:10.1007/BF02786970
  2. [AW24] Christos A. Athanasiadis and David G. Wagner. Veronese sections and interlacing matrices of polynomials and formal power series. arXiv:2404.12989. arXiv
  3. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  4. [Edr53] Albert Edrei. Proof of a Conjecture of Schoenberg on the Generating Function of a Totally Positive Sequence. Canadian Journal of Mathematics, 5:86–94, 1953. doi:10.4153/CJM-1953-010-3
  5. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.