A085880 → x ↦ x+1 → basis A013610

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
111
2336
318361872
41354054051351080
51134453668044536113418144
610206510301020601020605103010206326592
796228577368144342019245601443420577368962286158592
89382236567561197026833283780532837805197026836567561938223120092544
99382230750578402627024405254048806567561005254048802627024407505784093822302401850880
1095698746861288714344515485680386946641205804199612058041996803869466434451548568612887149569874648997757952
119917870049917870040446304151801190144404802082752708402499303250082082752708401190144404804463041518099178700409917870041015589892096
12104137635421145513989625727569948101718270984430343654196886048111587564044811158756404343654196886017182709844305727569948101145513989621041376354221327387734016
131105461052921326553263504729604294927224320143164240547203221195408755251539126410214460128980887552515391264547203221195402432014316424072960429492721326553263504110546105292452796847276032
14118442255670015397493237100923849594226003387448512162008468621280405001524351830472900203246910729720020324691072972001524351830472900846862128040500338744851216200923849594226001539749323710011844225567009702789584486400
151279176361236017908469057304011640504887247604656201954899040128045553759723602560911075194472038413666127917080439013327176195203841366612791708025609110751944720128045553759723604656201954899040116405048872476017908469057304012791763612360209580255024906240
Technical details
Node id
n-d0556513d3c9ffc3 · revision 0 · JSON
Definition source
derived:basis_map_A013610
Fingerprint
f6-77a7ed3b1d5f257e

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: yes
  • γ-positive (gamma_positive): yes
  • 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,         3;
   3:       18,        36,         18;
   4:      135,       405,        405,        135;
   5:     1134,      4536,       6804,       4536,        1134;
   6:    10206,     51030,     102060,     102060,       51030,       10206;
   7:    96228,    577368,    1443420,    1924560,     1443420,      577368,      96228;
   8:   938223,   6567561,   19702683,   32837805,    32837805,    19702683,    6567561,     938223;
   9:  9382230,  75057840,  262702440,  525404880,   656756100,   525404880,  262702440,   75057840,   9382230;
  10: 95698746, 861288714, 3445154856, 8038694664, 12058041996, 12058041996, 8038694664, 3445154856, 861288714, 95698746;
%F Formula
The row polynomials satisfy n*P(n,x) = (12*n-18+(12*n-18)*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 + (12*n - 18)*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 + (12*n - 18)*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.