A134059 → basis A008277

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Submission text ?

Triangle begins:
  0:    1;
  1:    6,     3;
  2:   12,    15,      3;
  3:   24,    57,     27,      3;
  4:   48,   195,    165,     42,      3;
  5:   96,   633,    855,    375,     60,      3;
  6:  192,  1995,   4053,   2730,    735,     81,     3;
  7:  384,  6177,  18207,  17703,   7140,   1302,   105,    3;
  8:  768, 18915,  79005, 106722,  60543,  16254,  2142,  132,   3;
  9: 1536, 57513, 334935, 612615, 469980, 174321, 33390, 3330, 162, 3;

The row polynomials satisfy (n-1)*P(n,x) = (2*n-2+(n-1)*x)*P(n-1,x) + (n-1)*x*d/dx P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 6 + 3*x.

P[0, x_] := 1;
P[1, x_] := 6 + 3*x;
P[n_, x_] := P[n, x] = Expand[Together[((2*n - 2 + (n - 1)*x)*P[n - 1, x] + (n - 1)*x*D[P[n - 1, x], x])/(n - 1)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten

P(N) = {my(v = vector(N + 1)); v[1] = 1; v[2] = 6 + 3*x; for(n = 2, N, my(i = n + 1); v[i] = ((2*n - 2 + (n - 1)*x)*v[i - 1] + (n - 1)*x*deriv(v[i - 1], x))/(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)

Properties

• Real-rooted? Every row P_n, n ≥ 0, is zero or real-rooted with all roots in (−∞, 0]
  by Ray basis map theorem
• Coefficients of one sign? Every nonzero row, n ≥ 0: the coefficients of P_n have one sign
  derived from Ray basis map theorem
• Hadamard kernel (Malo)? Rows P_n, n ≥ 0, are Hadamard kernels (preserve real-rootedness)
  derived from Ray basis map theorem

Proof chains ? JSON

• Ray basis map theorem [MW08, Thm 2] polytool RealRooted rayBasisMap_maps_realRootedIn_iff ? step ›

  • from Triangle T(n, k) = 3*binomial(n,k) with T(0, 0) = 1, read by rows.?
    • Row-hypergeometric rows (multiplier sequences) [SP14; Bra15, Thm 7.1 of arXiv:1410.6601] polytool RealRooted RealRooted.isPFMultiplierSequence_eval_of_roots_nonpos RealRooted RealRooted.isPFMultiplierSequence_inv_ascPochhammer RealRooted RealRooted.IsPFMultiplierSequence.mul ? step › direct check
    • Liu–Wang theorem [LW07, Thm 2.1, Cor 2.4] ? step › direct check
    • Iterated real-rootedness preservers [SP14; Bra15, Thm 7.1 of arXiv:1410.6601; Bra06, Cor 3.5] polytool ? step › direct check

Related ?

Same fingerprint ?

• A135089 → basis A008277
• A134346 → basis A008277
• A038338 → basis A008277
• basis-map coefficients of A113214, shifted → basis A013609 → basis A008277
• A131431 → x ↦ x+1 → basis A008277
• A178821 → basis A013609 → basis A008277
• A258758 → basis A008277
• A135065 → basis A008277
• A156992 → basis A008277 → reverse
• A124860 → basis A008277
• A038338 → basis A013609 → basis A008277
• A356546 → basis A008277
• A196347 → basis A013609 → basis A008277
• A085881 → basis A013609 → basis A008277
• A134058 → basis A008277
• A356546 → basis A013609 → basis A008277
• A085881 → basis A008277
• A038330 → basis A013611 → basis A008277
• A156992 → basis A008277
• A038325 → basis A013609 → basis A008277
• A178820 → basis A008277
• A178820 → basis A013609 → basis A008277
• A178822 → basis A008277
• A135838 → basis A008277
• A027465 → basis A013611 → basis A008277
• A085880 → D → basis A008277
• A143494: Triangle read by rows: 2-Stirling numbers of the second kind.
• A132200 → basis A008277
• basis-map coefficients of A113214, shifted → basis A008277
• A038208 → basis A008277
• A003506 → basis A008277
• A028326 → D → basis A008277
• A120910 → basis A013610 → basis A008277
• A126351: Triangle read by rows: matrix product of the Stirling numbers of the second kind with the binomial coefficient…
• A028326 → basis A013609 → basis A008277
• A038221 → basis A013609 → basis A008277
• A156992 → basis A013609 → basis A008277
• A376827 → basis A008277
• basis-map coefficients of A112227 → x ↦ x+1 → basis A008277
• A085880 → basis A008277
• A038221 → basis A008277
• A344565 → basis A008277
• A038325 → basis A008277
• A178822 → basis A013609 → basis A008277
• A085880 → basis A013609 → basis A008277
• basis-map coefficients of A021012 → basis A008277 → D+1
• basis-map coefficients of A113214, shifted → D → basis A008277
• A126351 → reverse
• A143494 → reverse
• A028326 → basis A008277
• basis-map coefficients of A026729, shifted → basis A007318 → basis A008277
• A196347 → basis A008277
• A003506 → D → basis A008277
• A094305 → basis A008277
• basis-map coefficients of A127647 → basis A008277
• A178821 → basis A008277
• A038208 → D → basis A008277

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. [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
5. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.