A085880 → basis A013610 → reverse

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in (−∞, 0]coefficients of one signHadamard kernelinterlacing (weak)

Recurrence

\(\left(n\right)\,P_{n}(x) = \left(-18 - 12\,x + 12\,n + 8\,n x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
111
2325
31824850
413527018040625
511343024302413442248750
610206340204536030240100801344131250
7962283849126415205702402851207603284482062500
8938223437837487567489729720648648025945925765765491233515625
993822305003856011675664015567552012972960069189120230630404392960366080558593750
109569874657419247615311799362381835456238183545615878903047057290242016368643360614424893449496093750
11991787004661191336019835740080352635379204114079424032912635392182847974406965637120174140928025798656017199104164023437500
121041376354276367599308254558664360509117328720678823104960633568231296422378820864201132771840670442572801489872384019864965121203937282870410156250
131105461052928843688423363242685755232720596834496010808952517440115295493519368967427273728512424415641621351017318406326227353601265245470721533630873685201715250784179687500
14118442255670010264995491400410599819656001003688448048001672814080080002007376896096001784335018752001189556679168005947783395840022028827392000587435397120010680643584001186738176006085836800906860351562500
15127917636123601193897937153605173557727665601379615394044160252929488908096033723931854412803372393185441280256944242700288014988414157516806661517403340802220505801113605383044366336089717406105609201785241604381802496016323486328125000
Technical details
Node id
n-d16ab8907dc7093c · revision 0 · JSON
Definition source
derived:reversal
Fingerprint
f6-f06e51c139cfae05

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 -1)
  • 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

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:        1;
   2:        3,         2;
   3:       18,        24,          8;
   4:      135,       270,        180,         40;
   5:     1134,      3024,       3024,       1344,        224;
   6:    10206,     34020,      45360,      30240,      10080,       1344;
   7:    96228,    384912,     641520,     570240,     285120,      76032,      8448;
   8:   938223,   4378374,    8756748,    9729720,    6486480,    2594592,    576576,     54912;
   9:  9382230,  50038560,  116756640,  155675520,  129729600,   69189120,  23063040,   4392960,   366080;
  10: 95698746, 574192476, 1531179936, 2381835456, 2381835456, 1587890304, 705729024, 201636864, 33606144, 2489344;
%F Formula
The row polynomials satisfy n*P(n,x) = (12*n-18+(8*n-12)*x)*P(n-1,x) for n >= 2, with P(1,x) = 1.
%t Mathematica
P[1, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((12*n - 18 + (8*n - 12)*x)*P[n - 1, x])/(n)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 1; for(n = 2, N, my(i = n); v[i] = ((12*n - 18 + (8*n - 12)*x)*v[i - 1])/(n)); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i, v[i])))};
T(10)

polytool c48629374597

Properties

Proof chains ? JSON

Same fingerprint ?

References

  1. [Bra06] Petter Brändén. On linear transformations preserving the Pólya frequency property. Transactions of the American Mathematical Society, 358(8):3697–3716, February 2006. doi:10.1090/s0002-9947-06-03856-6
  2. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  3. [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
  4. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.