basis-map coefficients of A297191, shifted → 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
\(P_{n}(x) = \left(1 + 4\,x + 4\,x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14x15x16x17x18x19x20x21x22x23x24x25x26x27x28Pn(1)
011
11449
21824321681
31126016024019264729
411611244811201792179210242566561
5120180960336080641344015360115205120102459049
612426417607920253445913610137612672011264067584245764096531441
71283642912160166406419219243929676876810250241025024745472372736114688163844782969
8132480448029120139776512512146432032947205857280820019289456647454720458752019660805242886553643046721
9136612652848960274176118809640734721120204824893440448081926517555276038144701890565013504026738688100270082359296262144387420489
10140760912077520496128248064099225603224832085995520189190144343982080515973120635043840635043840508035072317521920149422080498073601048576010485763486784401
1114492412320117040842688477523221829632818611202546790406621655041444724736264866201640748646405239111680558838579248898375683451650048191758336080740352024222105646137344419430431381059609
121481104161921700161360128861414444301312188280576669442048200832614451121029121107622297620448411648321332183044284429107248199827456453645434883528353382422284337152111421685764244635648115762790420132659216777216282429536481
13152130020800239200210496014734720841984003999424001599769600543921664015823175680395579392008520171520015823175680025317081088034810986496040954101760040954101760034487664640024141365248013795065856062704844800218103808005452595200872415232671088642541865828329
14156151226208327600314496024111360151557120795674880353633280013438064640439791206401246075084803067261747206572703744001226904698880199372013568028146637209603440144547840362120478720032590843084802483111854080158016208896082443239424034351349760010992431923225367150592375809638426843545622876792454961

Generated b-files: A001019 (row sums), A100062 (row sums) ?

Computed in your browser ?

Technical details
Node id
n-5c5dbc66494212e8 · revision 1 · JSON
Definition source
derived:basis_map_A013609
Fingerprint
f6-90334921cba1a1bb

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: 1,  4,   4;
  2: 1,  8,  24,   32,    16;
  3: 1, 12,  60,  160,   240,    192,      64;
  4: 1, 16, 112,  448,  1120,   1792,    1792,    1024,      256;
  5: 1, 20, 180,  960,  3360,   8064,   13440,   15360,    11520,     5120,     1024;
  6: 1, 24, 264, 1760,  7920,  25344,   59136,  101376,   126720,   112640,    67584,    24576,     4096;
  7: 1, 28, 364, 2912, 16016,  64064,  192192,  439296,   768768,  1025024,  1025024,   745472,   372736,   114688,    16384;
  8: 1, 32, 480, 4480, 29120, 139776,  512512, 1464320,  3294720,  5857280,  8200192,  8945664,  7454720,  4587520,  1966080,   524288,    65536;
  9: 1, 36, 612, 6528, 48960, 274176, 1188096, 4073472, 11202048, 24893440, 44808192, 65175552, 76038144, 70189056, 50135040, 26738688, 10027008, 2359296, 262144;
%F Formula
The row polynomials satisfy P(n,x) = (1+4*x+4*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[(1 + 4*x + 4*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] = (1 + 4*x + 4*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-20c0b01c4fb345ed
  • 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-20c0b01c4fb345ed
  • 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-20c0b01c4fb345ed

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

Candidate equalities (1)

Definitions that agree on the stored rows without an all-n certificate.

Same fingerprint (4)

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