A038271 → basis A013610 → basis A013609

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Submission text ?

Triangle begins:
  0:             1;
  1:            27,             30;
  2:           729,           1620,             900;
  3:         19683,          65610,           72900,           27000;
  4:        531441,        2361960,         3936600,         2916000,           810000;
  5:      14348907,       79716150,       177147000,       196830000,        109350000,         24300000;
  6:     387420489,     2582803260,      7174453500,     10628820000,       8857350000,       3936600000,        729000000;
  7:   10460353203,    81358302690,    271194342300,    502211745000,     558013050000,     372008700000,     137781000000,     21870000000;
  8:  282429536481,  2510484768720,   9762996322800,  21695547384000,   30132704700000,   26784626400000,   14880348000000,   4723920000000,    656100000000;
  9: 7625597484987, 76255974849870, 338915443777200, 878669669052000, 1464449448420000, 1627166053800000, 1205308188000000, 573956280000000, 159432300000000, 19683000000000;

The row polynomials satisfy P(n,x) = (27+30*x)*P(n-1,x) for n >= 1, with P(0,x) = 1.

P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[(27 + 30*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten

P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = (27 + 30*x)*v[i - 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 Geometric basis map (elementary)
• Coefficients of one sign? Every nonzero row, n ≥ 0: the coefficients of P_n have one sign
  derived from Geometric basis map (elementary)
• Hadamard kernel (Malo)? Rows P_n, n ≥ 0, are Hadamard kernels (preserve real-rootedness)
  derived from Geometric basis map (elementary)

Proof chains ? JSON

• Geometric basis map (elementary) polytool ? step ›

  • from basis_map_A013610 of Triangle whose (i,j)-th entry is binomial(i,j)*7^(i-j)*5^j.?
    • Geometric basis map (elementary) polytool ? step ›

      • from Triangle whose (i,j)-th entry is binomial(i,j)*7^(i-j)*5^j.?
        • 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
        • Parent-row provers of polytool polytool ? step › direct check

Related ?

Same fingerprint ?

• A038291 → x ↦ x/(x+1)
• A013622 → basis A013609 → basis A013609
• A038319 → basis A013611 → basis A013609
• A038331 → basis A013609 → basis A013610
• A038255 → basis A013610 → basis A013610
• A038284 → basis A007318 → basis A013610
• A038323 → basis A013609
• A038323 → basis A013609 → D
• A038335 → x ↦ x+1 → basis A013610

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.