A200536 → basis A007318

nonnegative coefficients only rational roots

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

Recurrence
\(P_{n}(x) = \left(6 + 7\,x + 2\,x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
167215
2368473284225
321675610988473668483375
412966048123121428010321476013682241650625
57776453601188001839601865101293676217020440440056032759375
64665632659210458722026080264438024496921651609816564293820750401291213446411390625
72799362286144865468820130768321405843726097232346258213600311078208641401081190392248528356163136128170859375

Generated b-files: A001024 (row sums) ?

Computed in your browser ?

Technical details
Node id
n-a19ad5e2037d7c6a · revision 1 · JSON
Definition source
derived:basis_map_A007318
Fingerprint
f6-10e88990a58171dc

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:        6,         7,         2;
  2:       36,        84,        73,         28,          4;
  3:      216,       756,      1098,        847,        366,         84,          8;
  4:     1296,      6048,     12312,      14280,      10321,       4760,       1368,        224,         16;
  5:     7776,     45360,    118800,     183960,     186510,     129367,      62170,      20440,       4400,        560,         32;
  6:    46656,    326592,   1045872,    2026080,    2644380,    2449692,    1651609,     816564,     293820,      75040,      12912,      1344,        64;
  7:   279936,   2286144,   8654688,   20130768,   32140584,   37260972,   32346258,   21360031,   10782086,    4140108,    1190392,    248528,     35616,     3136,      128;
  8:  1679616,  15676416,  68491008,  185939712,  351068256,  488811456,  519185520,  429105936,  278905249,  143035312,   57687280,  18104128,   4334176,   765184,    93952,    7168,    256;
  9: 10077696, 105815808, 524040192, 1626428160, 3544969536, 5762225952, 7238929824, 7186557168, 5715544086, 3668760487, 1905181362, 798506352, 268108512, 71138592, 14588352, 2231040, 239616, 16128, 512;
%F Formula
The row polynomials satisfy P(n,x) = (6+7*x+2*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[(6 + 7*x + 2*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] = (6 + 7*x + 2*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-6e97878f95ac8f6d
  • 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-6e97878f95ac8f6d
  • 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-6e97878f95ac8f6d

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.