A038321 → basis A007318 → D

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Submission text ?

Triangle begins:
  0:             252,               98;
  1:            6804,             5292,             1029;
  2:          163296,           190512,            74088,             9604;
  3:         3674160,          5715360,          3333960,           864360,            84035;
  4:        79361856,        154314720,        120022560,         46675440,          9075780,          705894;
  5:      1666598976,       3888730944,       3780710640,       1960368480,        571774140,        88942644,         5764801;
  6:     34284321792,      93329542656,     108884466432,      70573265280,      27445158720,      6403870368,       830131344,       46118408;
  7:    694257516288,    2159912272896,    2939880593664,    2286573795072,    1111528928160,    345808999872,     67240638864,     7471182096,     363182463;
  8:  13885150325760,   48598026140160,   75596929551360,   68597213852160,   40015041413760,  15561404994240,   4034438331840,   672406388640,   65372843340,   2824752490;
  9: 274925976450048, 1069156575083520, 1871024006396160, 1940321191818240, 1320496366654080, 616231637771904, 199704697426080, 44378821650240, 6471911490660, 559300993020, 21750594173;

The row polynomials satisfy (n+1)*P(n,x) = (18*n+36+(7*n+14)*x)*P(n-1,x) for n >= 1, with P(0,x) = 252 + 98*x.

P[0, x_] := 252 + 98*x;
P[n_, x_] := P[n, x] = Expand[Together[((18*n + 36 + (7*n + 14)*x)*P[n - 1, x])/(n + 1)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten

P(N) = {my(v = vector(N + 1)); v[1] = 252 + 98*x; for(n = 1, N, my(i = n + 1); v[i] = ((18*n + 36 + (7*n + 14)*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)

Properties

• Real-rooted? Every row P_n, n ≥ 0, is zero or real-rooted with all roots in (−∞, 0]
  by Laguerre’s theorem on differential operators
• Coefficients of one sign? Every nonzero row, n ≥ 0: the coefficients of P_n have one sign
  derived from Laguerre’s theorem on differential operators
• Hadamard kernel (Malo)? Rows P_n, n ≥ 0, are Hadamard kernels (preserve real-rootedness)
  derived from Laguerre’s theorem on differential operators
• Interlacing of consecutive rows? Rows P_(m-1), P_m interlace (weak, unordered) for every m ≥ 1
  by Laguerre’s theorem on differential operators

Proof chains ? JSON

• Laguerre’s theorem on differential operators [SP14] polytool ? step ›

  • from basis_map_A007318 of Triangle whose (i,j)-th entry is binomial(i,j)*11^(i-j)*7^j.?
    • Geometric basis map (elementary) polytool ? step ›

      • from Triangle whose (i,j)-th entry is binomial(i,j)*11^(i-j)*7^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
        • Parent-row provers of polytool polytool ? step › direct check
        • Iterated real-rootedness preservers [SP14; Bra15, Thm 7.1 of arXiv:1410.6601; Bra06, Cor 3.5] polytool ? step › direct check
    • Affine, reversal and Möbius substitutions (elementary) polytool ? step ›

      • from Triangle whose (i,j)-th entry is binomial(i,j)*11^(i-j)*7^j.?
        • ↑ Row-hypergeometric rows (multiplier sequences) (above)
        • ↑ Liu–Wang theorem (above)
        • ↑ Parent-row provers of polytool (above)
        • ↑ Iterated real-rootedness preservers (above)

Related ?

Same fingerprint ?

• A038277 → x ↦ x/(x+1) → reverse
• A013620 → basis A013610 → basis A013611
• A038277 → x ↦ x/(x+1) → D
• A038277 → x ↦ x/(x+1)
• A038321 → basis A007318 → reverse
• A038321 → basis A007318

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.