basis-map coefficients of A112227 → x ↦ x+1 → basis A013611

nonnegative coefficientsonly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9Pn(1)
14161636
28489664216
3161283845122561296
43232012802560256010247776
5647683840102401536012288409646656
61281792107523584071680860165734416384279936
7256409628672114688286720458752458752262144655361679616
85129216737283440641032192206438427525122359296117964826214410077696
Technical details
Node id
n-a535589f024a4075 · revision 0 · JSON
Definition source
derived:basis_map_A013611
Fingerprint
f6-11aec07ce60b6d61

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:    4,    16,     16;
   2:    8,    48,     96,      64;
   3:   16,   128,    384,     512,      256;
   4:   32,   320,   1280,    2560,     2560,     1024;
   5:   64,   768,   3840,   10240,    15360,    12288,     4096;
   6:  128,  1792,  10752,   35840,    71680,    86016,    57344,    16384;
   7:  256,  4096,  28672,  114688,   286720,   458752,   458752,   262144,    65536;
   8:  512,  9216,  73728,  344064,  1032192,  2064384,  2752512,  2359296,  1179648,   262144;
   9: 1024, 20480, 184320,  983040,  3440640,  8257536, 13762560, 15728640, 11796480,  5242880,  1048576;
  10: 2048, 45056, 450560, 2703360, 10813440, 30277632, 60555264, 86507520, 86507520, 57671680, 23068672, 4194304;
%F Formula
The row polynomials satisfy P(n,x) = (2+4*x)*P(n-1,x) for n >= 2, with P(1,x) = 4 + 16*x + 16*x^2.
%t Mathematica
P[1, x_] := 4 + 16*x + 16*x^2;
P[n_, x_] := P[n, x] = Expand[(2 + 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] = 4 + 16*x + 16*x^2; for(n = 2, N, my(i = n); v[i] = (2 + 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.