basis-map coefficients of A021012 → Veronese 2 → D

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-3 + n\right)\,P_{n}(x) = \left(-2\,x + 5\,n x - 4\,n^{2} x + n^{3} x\right)\,P_{n-2}(x)\)
\(P_{1}(x) = 0\)
\(P_{2}(x) = 0\)
\(P_{3}(x) = 2\)

Rows ?

nx0x1x2x3x4x5x6Pn(1)
10
20
322
40
504848
60
70021602160
80
9000161280161280
100
1100001814400018144000
120
130000028740096002874009600
140
15000000610248038400610248038400
Technical details
Node id
n-7464280d5d702f91 · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-1641c37dbfc60bc3

Observed on the stored rows ?

  • Degrees: -1, -1, 0, -1, 1, -1, 2, -1, 3, -1, 4, -1, 5, -1, 6 (half affine: slope 1, intercept -3)
  • 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: 0;
   2: 0;
   3: 2;
   4: 0;
   5: 0, 48;
   6: 0;
   7: 0,  0, 2160;
   8: 0;
   9: 0,  0,    0, 161280;
  10: 0;
%F Formula
The row polynomials satisfy (n-3)*P(n,x) = (n^3-4*n^2+5*n-2)*x*P(n-2,x) for n >= 4, with P(1,x) = 0, P(2,x) = 0, P(3,x) = 2.
%t Mathematica
P[1, x_] := 0;
P[2, x_] := 0;
P[3, x_] := 2;
P[n_, x_] := P[n, x] = Expand[Together[((n^3 - 4*n^2 + 5*n - 2)*x*P[n - 2, x])/(n - 3)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 0; v[2] = 0; v[3] = 2; for(n = 4, N, my(i = n); v[i] = ((n^3 - 4*n^2 + 5*n - 2)*x*v[i - 2])/(n - 3)); 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. [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
  4. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.