basis-map coefficients of A030528, shifted → (θ+1)² → x ↦ x+1

palindromiconly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1-4-4-8
2918936
3-16-48-48-16-128
42510015010025400
5-36-180-360-360-180-36-1152
649294735980735294493136
7-64-448-1344-2240-2240-1344-448-64-8192
881648226845365670453622686488120736
9-100-900-3600-8400-12600-12600-8400-3600-900-100-51200
1012112105445145202541030492254101452054451210121123904
11-144-1584-7920-23760-47520-66528-66528-47520-23760-7920-1584-144-294912
1216920281115437180836551338481561561338488365537180111542028169692224
13-196-2548-15288-56056-140140-252252-336336-336336-252252-140140-56056-15288-2548-196-1605632
1422531502047581900225225450450675675772200675675450450225225819002047531502253686400
Technical details
Node id
n-70ffe10ed4131e9a · 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 0)
  • 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 = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:    1;
  1:   -4,   -4;
  2:    9,   18,     9;
  3:  -16,  -48,   -48,   -16;
  4:   25,  100,   150,   100,     25;
  5:  -36, -180,  -360,  -360,   -180,    -36;
  6:   49,  294,   735,   980,    735,    294,    49;
  7:  -64, -448, -1344, -2240,  -2240,  -1344,  -448,   -64;
  8:   81,  648,  2268,  4536,   5670,   4536,  2268,   648,   81;
  9: -100, -900, -3600, -8400, -12600, -12600, -8400, -3600, -900, -100;
%F Formula
The row polynomials satisfy n^2*P(n,x) = -(n^2+2*n+1+(n^2+2*n+1)*x)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[(-(n^2 + 2*n + 1 + (n^2 + 2*n + 1)*x)*P[n - 1, x])/(n^2)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = (-(n^2 + 2*n + 1 + (n^2 + 2*n + 1)*x)*v[i - 1])/(n^2)); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i - 1, v[i])))};
T(9)

polytool c48629374597

Properties

Proof chains ? JSON

Same fingerprint ?

References

  1. [Bra06] Petter Brändén. On linear transformations preserving the Pólya frequency property. Transactions of the American Mathematical Society, 358(8):3697–3716, February 2006. doi:10.1090/s0002-9947-06-03856-6
  2. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  3. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.