A085881 → basis A007318 → D

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-1 + n\right)\,P_{n}(x) = \left(-2\,n - n x + 4\,n^{2} + 2\,n^{2} x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
111
212618
318018045405
433605040252042011340
575600151200113400378004725382725
619958404989600498960024948006237006237015155910
7605404801816214402270268001513512005675670011351340945945689593905
820756736007264857600108972864009081072000454053600013621608002270268001621620035464829400
9793945152003175780608005557616064005557616064003473510040001389404016003473510040049621572003101348252034794586825
103352212864000150849578880003016991577600035198235072000263986763040001319933815200043997793840009428098680001178512335006547290750128870323832250
1115487223431680077436117158400017423126360640002323083514752000203269807540800012196188452448005081745188520001451927196720002722363493850030248483265001512424163258930713441574925
1277717703038976004274473667143680010686184167859200016029276251788800016029276251788800011220493376252160056102466881260800200365953147360005009148828684000834858138114000834858138114003794809718700672239157238548900
13420970891461120000252582534876672000069460197091084800001157669951518080000013023786954578400000104190295636627200006077767245469920000260475739091568000081398668466115000018088592992470000027132889488705000246662631715500010277609654812554619431525632098125
142448107645727744000015912699697230336000047738099091691008000087519848334766848000010939981041845856000009845982937661270400006563988625107513600003281994312553756800001230747867207658800003418744075576830000068374881511536600009323847478845900007769872899038250029884126534762504764495026928215328750
Technical details
Node id
n-d687177931d5f117 · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-11aec07ce60b6d61

Observed on the stored rows ?

  • Degrees: -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 (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 = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:           0;
  1:           1;
  2:          12,            6;
  3:         180,          180,           45;
  4:        3360,         5040,         2520,          420;
  5:       75600,       151200,       113400,        37800,         4725;
  6:     1995840,      4989600,      4989600,      2494800,       623700,        62370;
  7:    60540480,    181621440,    227026800,    151351200,     56756700,     11351340,      945945;
  8:  2075673600,   7264857600,  10897286400,   9081072000,   4540536000,   1362160800,   227026800,   16216200;
  9: 79394515200, 317578060800, 555761606400, 555761606400, 347351004000, 138940401600, 34735100400, 4962157200, 310134825;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = (4*n^2-2*n+(2*n^2-n)*x)*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 1.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((4*n^2 - 2*n + (2*n^2 - n)*x)*P[n - 1, x])/(n - 1)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 0; v[2] = 1; for(n = 2, N, my(i = n + 1); v[i] = ((4*n^2 - 2*n + (2*n^2 - n)*x)*v[i - 1])/(n - 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)

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.