basis-map coefficients of A112227 → basis A013610 → reverse

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(3 + x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 9 + 6\,x + x^{2}\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9Pn(1)
196116
227279164
38110854121256
4243405270901511024
5729145812155401351814096
6218751035103283594518921116384
765611749620412136085670151225224165536
81968359049787326123630618102062268324271262144
Technical details
Node id
n-03b6ac0cdf658905 · revision 0 · JSON
Definition source
derived:reversal
Fingerprint
f6-f9762973ec1089d7

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:      9,      6,       1;
   2:     27,     27,       9,       1;
   3:     81,    108,      54,      12,      1;
   4:    243,    405,     270,      90,     15,      1;
   5:    729,   1458,    1215,     540,    135,     18,      1;
   6:   2187,   5103,    5103,    2835,    945,    189,     21,     1;
   7:   6561,  17496,   20412,   13608,   5670,   1512,    252,    24,    1;
   8:  19683,  59049,   78732,   61236,  30618,  10206,   2268,   324,   27,   1;
   9:  59049, 196830,  295245,  262440, 153090,  61236,  17010,  3240,  405,  30,  1;
  10: 177147, 649539, 1082565, 1082565, 721710, 336798, 112266, 26730, 4455, 495, 33, 1;
%F Formula
The row polynomials satisfy P(n,x) = (3+x)*P(n-1,x) for n >= 2, with P(1,x) = 9 + 6*x + x^2.
%t Mathematica
P[1, x_] := 9 + 6*x + x^2;
P[n_, x_] := P[n, x] = Expand[(3 + 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] = 9 + 6*x + x^2; for(n = 2, N, my(i = n); v[i] = (3 + 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.