A193685 → Pₙ + Pₙ₊₁

nonnegative coefficients

Proved for all n: all roots real what this means

Recurrence
\(P_{n}(x) = \left(5 + x\right)\,P_{n-1}(x) + \left(x\right)\,P_{n-1}'(x)\)
\(P_{0}(x) = 6 + x\)

Rows ?

nx0x1x2x3x4x5x6x7x8Pn(1)
0617
13012143
2150102191272
37507622352711775
437505322240745136111967
5187503568222171601577546183440
69375023284219087970291129901235571602045
7468750149080215689957532071872012534018626914496227

Computed in your browser ?

Technical details
Node id
n-b1b9b86e187f6cb4 · revision 1 · JSON
Definition source
derived:obreschkoff_combination
Fingerprint
f6-dfb4cc06d90ce2b1

Observed on the stored rows ?

  • Degrees: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 (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): no

OEIS matches ?

No OEIS matches.

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:        6,        1;
  1:       30,       12,        1;
  2:      150,      102,       19,        1;
  3:      750,      762,      235,       27,        1;
  4:     3750,     5322,     2407,      451,       36,       1;
  5:    18750,    35682,    22171,     6015,      775,      46,      1;
  6:    93750,   232842,   190879,    70291,    12990,    1235,     57,     1;
  7:   468750,  1490802,  1568995,   753207,   187201,   25340,   1862,    69,    1;
  8:  2343750,  9413562, 12473767,  7594651,  2438016,  440601,  45822,  2690,   82,  1;
  9: 11718750, 58825122, 96729931, 73230975, 29536795, 6844026, 944643, 78102, 3756, 96, 1;
%F Formula
The row polynomials satisfy P(n,x) = (5+x)*P(n-1,x) + x*d/dx P(n-1,x) for n >= 1, with P(0,x) = 6 + x.
%t Mathematica
P[0, x_] := 6 + x;
P[n_, x_] := P[n, x] = Expand[(5 + x)*P[n - 1, x] + x*D[P[n - 1, x], x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 6 + x; for(n = 1, N, my(i = n + 1); v[i] = (5 + x)*v[i - 1] + x*deriv(v[i - 1], x)); 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, +inf)
    Every polynomial of the sequence has only real roots, inside the stated interval.
    by the cited steps: e-76715f1adaa360d7

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. [ASW52] Michael Aissen, I. J. Schoenberg and A. M. Whitney. On the generating functions of totally positive sequences I. Journal d’Analyse Mathématique, 2(1):93–103, 1952. doi:10.1007/BF02786970
  2. [AW24] Christos A. Athanasiadis and David G. Wagner. Veronese sections and interlacing matrices of polynomials and formal power series. arXiv:2404.12989. arXiv
  3. [Edr53] Albert Edrei. Proof of a Conjecture of Schoenberg on the Generating Function of a Totally Positive Sequence. Canadian Journal of Mathematics, 5:86–94, 1953. doi:10.4153/CJM-1953-010-3
  4. [Fis06] Steve Fisk. Polynomials, roots, and interlacing. arXiv:math/0612833. arXiv
  5. [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
  6. [MW08] Shi-Mei Ma and Yi Wang. q-Eulerian polynomials and polynomials with only real zeros. The Electronic Journal of Combinatorics, 15(1):Research Paper 17, January 2008. doi:10.37236/741
  7. [Obr63] Nikola Obreschkoff. Verteilung und berechnung der nullstellen reeller polynome. Hochschulbücher für mathematik, VEB Deutscher Verlag der Wissenschaften, 1963.