basis-map coefficients of A113214, shifted → basis A013609 → θ+1

only rational roots

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

Recurrence

\(\left(1 + n x\right)\,P_{n}(x) = \left(-2 - 4\,x - 2\,x^{2} - 2\,n x - 2\,n x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1-2-4-6
24161232
3-8-48-72-32-160
41612828825680768
5-32-320-960-1280-800-192-3584
664768288051204800230444816384
7-128-1792-8064-17920-22400-16128-6272-1024-73728
Technical details
Node id
n-c14c1cf7f058cd0c · revision 0 · JSON
Definition source
derived:theta_plus_one
Fingerprint
f6-e99c3824c4864868

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: 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 = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:    1;
  1:   -2,    -4;
  2:    4,    16,     12;
  3:   -8,   -48,    -72,     -32;
  4:   16,   128,    288,     256,      80;
  5:  -32,  -320,   -960,   -1280,    -800,    -192;
  6:   64,   768,   2880,    5120,    4800,    2304,     448;
  7: -128, -1792,  -8064,  -17920,  -22400,  -16128,   -6272,   -1024;
  8:  256,  4096,  21504,   57344,   89600,   86016,   50176,   16384,   2304;
  9: -512, -9216, -55296, -172032, -322560, -387072, -301056, -147456, -41472, -5120;
%F Formula
The row polynomials satisfy (1+n*x)*P(n,x) = -(2+(2*n+4)*x+(2*n+2)*x^2)*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[(-(2 + (2*n + 4)*x + (2*n + 2)*x^2)*P[n - 1, x])/(1 + n*x)]];
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] = (-(2 + (2*n + 4)*x + (2*n + 2)*x^2)*v[i - 1])/(1 + n*x)); 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.