basis-map coefficients of A026729, shifted → (θ+1)² → basis A013611

only rational roots

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

Recurrence

\(\left(1 - 2\,n + n^{2}\right)\,P_{n}(x) = \left(-n^{2} - 4\,n^{2} x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
111
2-4-16-20
3972144225
4-16-192-768-1024-2000
52540024006400640015625
6-36-720-5760-23040-46080-36864-112500
74911761176062720188160301056200704765625
8-64-1792-21504-143360-573440-1376256-1835008-1048576-5000000
Technical details
Node id
n-2779a75fc60be9a6 · revision 0 · JSON
Definition source
derived:basis_map_A013611
Fingerprint
f6-03d7b8417365c509

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,   -16;
   3:    9,    72,    144;
   4:  -16,  -192,   -768,   -1024;
   5:   25,   400,   2400,    6400,     6400;
   6:  -36,  -720,  -5760,  -23040,   -46080,    -36864;
   7:   49,  1176,  11760,   62720,   188160,    301056,    200704;
   8:  -64, -1792, -21504, -143360,  -573440,  -1376256,  -1835008,  -1048576;
   9:   81,  2592,  36288,  290304,  1451520,   4644864,   9289728,  10616832,   5308416;
  10: -100, -3600, -57600, -537600, -3225600, -12902400, -34406400, -58982400, -58982400, -26214400;
%F Formula
The row polynomials satisfy (n^2-2*n+1)*P(n,x) = -(n^2+4*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 + 4*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 + 4*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.