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

palindromiconly rational roots

Proved for all n all roots real, in (−∞, −1]coefficients of one signHadamard kernelinterlacing (weak)

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
111
2-2-2-4
336312
4-4-12-12-4-32
55203020580
6-6-30-60-60-30-6-192
7742105140105427448
8-8-56-168-280-280-168-56-8-1024
99722525046305042527292304
10-10-90-360-840-1260-1260-840-360-90-10-5120
1111110495132023102772231013204951101111264
12-12-132-660-1980-3960-5544-5544-3960-1980-660-132-12-24576
131315685828606435102961201210296643528608581561353248
14-14-182-1092-4004-10010-18018-24024-24024-18018-10010-4004-1092-182-14-114688
151521013655460150153003045045514804504530030150155460136521015245760
Technical details
Node id
n-4562321cda9e7389 · revision 0 · JSON
Definition source
derived:shift_x_plus_one
Fingerprint
f6-77a7ed3b1d5f257e

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: yes
  • 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,  -2;
   3:   3,   6,    3;
   4:  -4, -12,  -12,   -4;
   5:   5,  20,   30,   20,     5;
   6:  -6, -30,  -60,  -60,   -30,    -6;
   7:   7,  42,  105,  140,   105,    42,    7;
   8:  -8, -56, -168, -280,  -280,  -168,  -56,   -8;
   9:   9,  72,  252,  504,   630,   504,  252,   72,   9;
  10: -10, -90, -360, -840, -1260, -1260, -840, -360, -90, -10;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = -(n+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 + 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 + 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.