basis-map coefficients of A112227 → basis A013610 → basis A007318

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(4 + 3\,x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 16 + 24\,x + 9\,x^{2}\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9Pn(1)
11624949
26414410827343
3256768864432812401
41024384057604320162024316807
54096184323456034560194405832729117649
6163848601619353624192018144081648204122187823543
7655363932161032192154828814515208709123265926998465615764801
8262144176947253084169289728104509447838208391910412597122361961968340353607
Technical details
Node id
n-b7a274e8348d5af4 · revision 0 · JSON
Definition source
derived:shift_x_plus_one
Fingerprint
f6-c91d5d506c107735

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,       24,         9;
   2:      64,      144,       108,        27;
   3:     256,      768,       864,       432,        81;
   4:    1024,     3840,      5760,      4320,      1620,       243;
   5:    4096,    18432,     34560,     34560,     19440,      5832,       729;
   6:   16384,    86016,    193536,    241920,    181440,     81648,     20412,      2187;
   7:   65536,   393216,   1032192,   1548288,   1451520,    870912,    326592,     69984,     6561;
   8:  262144,  1769472,   5308416,   9289728,  10450944,   7838208,   3919104,   1259712,   236196,    19683;
   9: 1048576,  7864320,  26542080,  53084160,  69672960,  62705664,  39191040,  16796160,  4723920,   787320,   59049;
  10: 4194304, 34603008, 129761280, 291962880, 437944320, 459841536, 344881152, 184757760, 69284160, 17321040, 2598156, 177147;
%F Formula
The row polynomials satisfy P(n,x) = (4+3*x)*P(n-1,x) for n >= 2, with P(1,x) = 16 + 24*x + 9*x^2.
%t Mathematica
P[1, x_] := 16 + 24*x + 9*x^2;
P[n_, x_] := P[n, x] = Expand[(4 + 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] = 16 + 24*x + 9*x^2; for(n = 2, N, my(i = n); v[i] = (4 + 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.