A159854 → basis A013609

nonnegative coefficients only rational roots

Proved for all n: all roots real, in (−∞, 0] · coefficients of one sign · Hadamard kernel what this means

Recurrence
\(P_{n}(x) = \left(2 + 2\,x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1 + 4\,x + 4\,x^{2}\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9Pn(1)
01449
121016836
2424524816144
385615220012832576
416128416704656320642304
53228810882240272019527681289216
66464027526656992093445440179225636864
71281408678418816331523852829568144644096512147456

Generated b-files: A002063 (row sums) ?

Computed in your browser ?

Technical details
Node id
n-43cc6f2245a53e97 · revision 1 · JSON
Definition source
derived:basis_map_A013609
Fingerprint
f6-a681886699e85b8d

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 2)
  • 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

OEIS matches ?

A generated b-file is computed from the node's definition along the row alignment of its OEIS link and starts at the entry's offset. It is an identification on a finite prefix, not a proof that the node and the OEIS entry agree for every n.

OEIS submission text ?

Fields to paste into an OEIS submission: the example %e, the formula %F and programs %t (Mathematica) and %o (PARI/GP) that list the same rows. For an OEIS link the row numbers, the offset and the orientation are those of the entry, as matched; the matched terms were compared with the published ones, which identifies the node with the entry on a finite prefix, not for every n. The PARI/GP program is not machine-checked here.

The atlas's own rows: n = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:   1,    4,     4;
  1:   2,   10,    16,      8;
  2:   4,   24,    52,     48,     16;
  3:   8,   56,   152,    200,    128,     32;
  4:  16,  128,   416,    704,    656,    320,     64;
  5:  32,  288,  1088,   2240,   2720,   1952,    768,    128;
  6:  64,  640,  2752,   6656,   9920,   9344,   5440,   1792,    256;
  7: 128, 1408,  6784,  18816,  33152,  38528,  29568,  14464,   4096,   512;
  8: 256, 3072, 16384,  51200, 103936, 143360, 136192,  88064,  37120,  9216,  1024;
  9: 512, 6656, 38912, 135168, 310272, 494592, 559104, 448512, 250368, 92672, 20480, 2048;
%F Formula
The row polynomials satisfy P(n,x) = (2+2*x)*P(n-1,x) for n >= 1, with P(0,x) = 1 + 4*x + 4*x^2.
%t Mathematica
P[0, x_] := 1 + 4*x + 4*x^2;
P[n_, x_] := P[n, x] = Expand[(2 + 2*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 + 4*x + 4*x^2; for(n = 1, N, my(i = n + 1); v[i] = (2 + 2*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)

Generated with polytool c48629374597.

Proved properties

  • Real-rooted. Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
    Every polynomial of the sequence has only real roots, inside the stated interval.
    by the cited steps: e-4ff089327fda7415
  • Coefficients of one sign. Every nonzero row, n >= 0: the coefficients of P_n have one sign
    All coefficients of each polynomial have the same sign (after x -> -x when alternating).
    derived from the cited steps by a stated theorem: e-4ff089327fda7415
  • Hadamard kernel (Malo). Rows P_n, n >= 0, are Hadamard kernels (preserve real-rootedness)
    Multiplying the coefficients of any real-rooted polynomial termwise by those of a row (Hadamard product) gives a real-rooted polynomial again.
    derived from the cited steps by a stated theorem: e-4ff089327fda7415

Proof chains

1 incoming proof step. Each step is expanded back to the roots of the proof DAG, the theorem checks of a node's own rule. JSON

Same fingerprint (2)

Equal up to content, sign, reversal and a small index shift.