A286718 → 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
\(P_{n}(x) = \left(-1 + 3\,x + 3\,n\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1235
21021940
38019813527440
488024182079702816160
5123203649236360160653240243104720
6209440657324727596382185103275138517292094400
7418880013774800165238929826488321205558684556133218748171200
89634240032938680042137391627558090010335672923133600305159421870065611252451200
9250490240088530840001194388221684292251483514017654911543787148742244148409828266861968336321084800
1072642169600264254143200372931836264280279175940127194187410369768227857048156437876615210684968403050865590491162274713600
11232454942720086740590912001272658119004810087729138872491105152494015648408913503364714743394919615603148217445103031182001104216317714740679614976000
128135922995200031056571647360047145251892528039125026343066420214999078951669502585772070164710242759152731279884102316349525943250743705301295830305393266345314411545825369088000
133091650738176000120455749158528001884689286858144016281867567141072885545044029360032475482317072088344066798009801532017084236212021512163814019018746579691244646631805381903007138174660159432363378840132608000
141267576802652160005031435237644928008088593323593974407240972488585282724119190707534608161597158288208763284395331856696180487844900847714011288425112434603138622225891149108086751642875940520128272181087008147989122347829692788668965834752000

Generated b-files: A034000 (row sums), A225477 ?

Computed in your browser ?

Technical details
Node id
n-96d72c9c3aa93ee7 · revision 1 · JSON
Definition source
derived:basis_map_A013610
Fingerprint
f6-cfe67b6e4979d755

Observed on the stored rows ?

  • Degrees: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 (affine: slope 1, 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:          2,          3;
  2:         10,         21,           9;
  3:         80,        198,         135,         27;
  4:        880,       2418,        2079,        702,         81;
  5:      12320,      36492,       36360,      16065,       3240,       243;
  6:     209440,     657324,      727596,     382185,     103275,     13851,       729;
  7:    4188800,   13774800,    16523892,    9826488,    3212055,    586845,     56133,     2187;
  8:   96342400,  329386800,   421373916,  275580900,  103356729,  23133600,   3051594,   218700,   6561;
  9: 2504902400, 8853084000, 11943882216, 8429225148, 3514017654, 911543787, 148742244, 14840982, 826686, 19683;
%F Formula
The row polynomials satisfy P(n,x) = (3*n-1+3*x)*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[(3*n - 1 + 3*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; for(n = 1, N, my(i = n + 1); v[i] = (3*n - 1 + 3*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.

A225477: triangle, offset 0, from the row P0
%e Example
Triangle begins:
  0:          1;
  1:          2,          3;
  2:         10,         21,           9;
  3:         80,        198,         135,         27;
  4:        880,       2418,        2079,        702,         81;
  5:      12320,      36492,       36360,      16065,       3240,       243;
  6:     209440,     657324,      727596,     382185,     103275,     13851,       729;
  7:    4188800,   13774800,    16523892,    9826488,    3212055,    586845,     56133,     2187;
  8:   96342400,  329386800,   421373916,  275580900,  103356729,  23133600,   3051594,   218700,   6561;
  9: 2504902400, 8853084000, 11943882216, 8429225148, 3514017654, 911543787, 148742244, 14840982, 826686, 19683;
%F Formula
The row polynomials satisfy P(n,x) = (3*n-1+3*x)*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[(3*n - 1 + 3*x)*P[n - 1, x]];
Table[PadRight[CoefficientList[P[n, x], x], n + 1], {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] = (3*n - 1 + 3*x)*v[i - 1]); v};
row(n, p) = {my(c = Vecrev(p)); c = concat(c, vector(n + 1 - #c)); 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-ccb031147de5168b
  • 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-ccb031147de5168b
  • 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-ccb031147de5168b

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

No candidate equalities or related sequences.

References

  1. [LW07] Lily L. Liu and Yi Wang. A unified approach to polynomial sequences with only real zeros. Advances in Applied Mathematics, 38(4):542–560, May 2007. doi:10.1016/j.aam.2006.02.003