basis-map coefficients of A021012 → θ+1 → reverse

palindromicγ-positiveonly rational roots

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

Recurrence

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

Rows ?

nx0Pn(1)
111
2-2-2
366
4-24-24
5120120
6-720-720
750405040
8-40320-40320
9362880362880
10-3628800-3628800
113991680039916800
12-479001600-479001600
1362270208006227020800
14-87178291200-87178291200
1513076743680001307674368000
Technical details
Node id
n-7b27b0374667b1fe · revision 0 · JSON
Definition source
derived:reversal
Fingerprint
f6-edf6954a4cd8adfc

Observed on the stored rows ?

  • Degrees: 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (affine: slope 0, intercept 0)
  • 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:        1;
   2:       -2;
   3:        6;
   4:      -24;
   5:      120;
   6:     -720;
   7:     5040;
   8:   -40320;
   9:   362880;
  10: -3628800;
%F Formula
The row polynomials satisfy P(n,x) = -n*P(n-1,x) for n >= 2, with P(1,x) = 1.
%t Mathematica
P[1, x_] := 1;
P[n_, x_] := P[n, x] = Expand[-n*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 1; for(n = 2, N, my(i = n); v[i] = -n*v[i - 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. [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.