basis-map coefficients of A026729, shifted → (θ+1)² → basis A013610

only rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
111
2-4-12-16
395481144
4-16-144-432-432-1024
5253001350270020256400
6-36-540-3240-9720-14580-8748-36864
749882661526460595357144235721200704
8-64-1344-12096-60480-181440-326592-326592-139968-1048576
Technical details
Node id
n-54ce42663577e2e3 · revision 0 · JSON
Definition source
derived:basis_map_A013610
Fingerprint
f6-f9762973ec1089d7

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:   -4,   -12;
   3:    9,    54,     81;
   4:  -16,  -144,   -432,    -432;
   5:   25,   300,   1350,    2700,     2025;
   6:  -36,  -540,  -3240,   -9720,   -14580,    -8748;
   7:   49,   882,   6615,   26460,    59535,    71442,    35721;
   8:  -64, -1344, -12096,  -60480,  -181440,  -326592,  -326592,  -139968;
   9:   81,  1944,  20412,  122472,   459270,  1102248,  1653372,  1417176,   531441;
  10: -100, -2700, -32400, -226800, -1020600, -3061800, -6123600, -7873200, -5904900, -1968300;
%F Formula
The row polynomials satisfy (n^2-2*n+1)*P(n,x) = -(n^2+3*n^2*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 + 3*n^2*x)*P[n - 1, x])/(n^2 - 2*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 + 3*n^2*x)*v[i - 1])/(n^2 - 2*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.