A034870 → basis A013610

nonnegative coefficients only rational roots

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

Recurrence
\(P_{n}(x) = \left(4 + 12\,x + 9\,x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1412925
2169621621681625
364576216043204860291672915625
4256307216128483849072010886481648349926561390625
510241536010368041472010886401959552244944020995201180980393660590499765625
64096737286082563041280102643202463436843110144554273285196312034642080155889364251528531441244140625
71638434406433546242012774483026944249080832560431872960740352126097171212609717129457287845158520641934445244464104447829696103515625

Generated b-files: A009969 (row sums) ?

Computed in your browser ?

Technical details
Node id
n-1e083728b424e77f · revision 1 · JSON
Definition source
derived:basis_map_A013610
Fingerprint
f6-6b852c5cd7d4c499

Observed on the stored rows ?

  • Degrees: 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28 (affine: slope 2, intercept 0)
  • 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;
  1:      4,      12,        9;
  2:     16,      96,      216,       216,         81;
  3:     64,     576,     2160,      4320,       4860,        2916,         729;
  4:    256,    3072,    16128,     48384,      90720,      108864,       81648,        34992,         6561;
  5:   1024,   15360,   103680,    414720,    1088640,     1959552,     2449440,      2099520,      1180980,       393660,        59049;
  6:   4096,   73728,   608256,   3041280,   10264320,    24634368,    43110144,     55427328,     51963120,     34642080,     15588936,      4251528,       531441;
  7:  16384,  344064,  3354624,  20127744,   83026944,   249080832,   560431872,    960740352,   1260971712,   1260971712,    945728784,    515852064,    193444524,     44641044,      4782969;
  8:  65536, 1572864, 17694720, 123863040,  603832320,  2173796352,  5977939968,  12809871360,  21616657920,  28822210560,  30263321088,  24760899072,  15475561920,   7142567040,   2295825120,   459165024,    43046721;
  9: 262144, 7077888, 90243072, 721944576, 4060938240, 17055940608, 55431806976, 142538932224, 293986547712, 489977579520, 661469732352, 721603344384, 631402926336, 437125102848, 234174162240, 93669664896, 26344593252, 4649045868, 387420489;
%F Formula
The row polynomials satisfy P(n,x) = (4+12*x+9*x^2)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[(4 + 12*x + 9*x^2)*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; for(n = 1, N, my(i = n + 1); v[i] = (4 + 12*x + 9*x^2)*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-cb7f9b19b94bd36e
  • 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-cb7f9b19b94bd36e
  • 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-cb7f9b19b94bd36e

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 (1)

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