basis-map coefficients of A112227 → basis A013611 → reverse

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(4 + x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 16 + 8\,x + x^{2}\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9Pn(1)
1168125
26448121125
325625696161625
4102412806401602013125
5409661443840128024024115625
61638428672215048960224033628178125
76553613107211468857344179203584448321390625
82621445898245898243440641290243225653765763611953125
Technical details
Node id
n-6f3f150f98e11d9a · revision 0 · JSON
Definition source
derived:reversal
Fingerprint
f6-03d7b8417365c509

Observed on the stored rows ?

  • Degrees: 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 (affine: slope 1, intercept 1)
  • 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 = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:      16,        8,        1;
   2:      64,       48,       12,        1;
   3:     256,      256,       96,       16,       1;
   4:    1024,     1280,      640,      160,      20,       1;
   5:    4096,     6144,     3840,     1280,     240,      24,      1;
   6:   16384,    28672,    21504,     8960,    2240,     336,     28,     1;
   7:   65536,   131072,   114688,    57344,   17920,    3584,    448,    32,     1;
   8:  262144,   589824,   589824,   344064,  129024,   32256,   5376,   576,    36,   1;
   9: 1048576,  2621440,  2949120,  1966080,  860160,  258048,  53760,  7680,   720,  40,  1;
  10: 4194304, 11534336, 14417920, 10813440, 5406720, 1892352, 473088, 84480, 10560, 880, 44, 1;
%F Formula
The row polynomials satisfy P(n,x) = (4+x)*P(n-1,x) for n >= 2, with P(1,x) = 16 + 8*x + x^2.
%t Mathematica
P[1, x_] := 16 + 8*x + x^2;
P[n_, x_] := P[n, x] = Expand[(4 + x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 16 + 8*x + x^2; for(n = 2, N, my(i = n); v[i] = (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, v[i])))};
T(10)

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.