basis-map coefficients of A026729, shifted → θ+1 → basis A013609

only rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
111
2-2-4-6
33121227
4-4-24-48-32-108
554012016080405
6-6-60-240-480-480-192-1458
77844201120168013444485103
8-8-112-672-2240-4480-5376-3584-1024-17496
Technical details
Node id
n-130a8064cebe5f50 · revision 0 · JSON
Definition source
derived:basis_map_A013609
Fingerprint
f6-11aec07ce60b6d61

Observed on the stored rows ?

  • Degrees: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 (affine: slope 1, intercept -1)
  • Palindromic rows: no
  • γ-positive (gamma_positive): no
  • 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,   -4;
   3:   3,   12,    12;
   4:  -4,  -24,   -48,   -32;
   5:   5,   40,   120,   160,     80;
   6:  -6,  -60,  -240,  -480,   -480,   -192;
   7:   7,   84,   420,  1120,   1680,   1344,    448;
   8:  -8, -112,  -672, -2240,  -4480,  -5376,  -3584,  -1024;
   9:   9,  144,  1008,  4032,  10080,  16128,  16128,   9216,   2304;
  10: -10, -180, -1440, -6720, -20160, -40320, -53760, -46080, -23040, -5120;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = -(n+2*n*x)*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[Together[(-(n + 2*n*x)*P[n - 1, 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; for(n = 2, N, my(i = n); v[i] = (-(n + 2*n*x)*v[i - 1])/(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. [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.