Real-rooted atlas

A136124 → basis A013611 → basis A007318

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(6 + 4\,x + n\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
17411
2566016132
3504764384641716
4504096566896217625624024
55544012637611448051520115201024360360
66652801738272187926410761603443205836840965765760
78648640252586563138352021507136878080021360642867201638498017920

All 15 rows

Technical details
Node id
n-ecdb8c02d525a9b0 · revision 0 · JSON
Definition source
derived:shift_x_plus_one
Fingerprint
f6-47b873245365cff6

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): 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:          1;
  1:          7,          4;
  2:         56,         60,         16;
  3:        504,        764,        384,         64;
  4:       5040,       9656,       6896,       2176,        256;
  5:      55440,     126376,     114480,      51520,      11520,       1024;
  6:     665280,    1738272,    1879264,    1076160,     344320,      58368,      4096;
  7:    8648640,   25258656,   31383520,   21507136,    8780800,    2136064,    286720,    16384;
  8:  121080960,  388215744,  540403904,  426633984,  208959744,   65028096,  12558336,  1376256,   65536;
  9: 1816214400, 6307560000, 9658921536, 8561125376, 4840932096, 1811260416, 448487424, 70877184, 6488064, 262144;
%F Formula
The row polynomials satisfy P(n,x) = (n+6+4*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[(n + 6 + 4*x)*P[n - 1, 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] = (n + 6 + 4*x)*v[i - 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.