A028326 → basis A013609 → D

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
144
2161632
3489648192
41283843841281024
53201280192012803205120
6768384076807680384076824576
7179210752268803584026880107521792114688
84096286728601614336014336086016286724096524288
99216737282580485160966451205160962580487372892162359296
102048018432073728017203202580480258048017203207372801843202048010485760
1145056450560202752054067209461760113541129461760540672020275204505604505646137344
1298304108134454067201622016032440320454164484541644832440320162201605406720108134498304201326592
132129922555904140574724685824010543104016868966419680460816868966410543104046858240140574722555904212992872415232
144587525963776357826561312030723280076805904138247872184327872184325904138243280076801312030723578265659637764587523758096384
Technical details
Node id
n-04ad3839217d3125 · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-77a7ed3b1d5f257e

Observed on the stored rows ?

  • Degrees: -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 (affine: slope 1, intercept -1)
  • Palindromic rows: yes
  • γ-positive (gamma_positive): yes
  • Nonnegative coefficients (nonn): yes
  • 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:    0;
  1:    4;
  2:   16,    16;
  3:   48,    96,     48;
  4:  128,   384,    384,    128;
  5:  320,  1280,   1920,   1280,    320;
  6:  768,  3840,   7680,   7680,   3840,    768;
  7: 1792, 10752,  26880,  35840,  26880,  10752,   1792;
  8: 4096, 28672,  86016, 143360, 143360,  86016,  28672,  4096;
  9: 9216, 73728, 258048, 516096, 645120, 516096, 258048, 73728, 9216;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = (2*n+2*n*x)*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 4.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 4;
P[n_, x_] := P[n, x] = Expand[Together[((2*n + 2*n*x)*P[n - 1, x])/(n - 1)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 0; v[2] = 4; for(n = 2, N, my(i = n + 1); v[i] = ((2*n + 2*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 - 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. [LW07] Lily L. Liu and Yi Wang. A unified approach to polynomial sequences with only real zeros. Advances in Applied Mathematics, 38(4):542–560, May 2007. doi:10.1016/j.aam.2006.02.003
  4. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.