A120910 → basis A013611 → D

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Submission text ?

Triangle begins:
  0:      0;
  1:     12;
  2:     72,      96;
  3:    324,     864,      576;
  4:   1296,    5184,     6912,     3072;
  5:   4860,   25920,    51840,    46080,     15360;
  6:  17496,  116640,   311040,   414720,    276480,     73728;
  7:  61236,  489888,  1632960,  2903040,   2903040,   1548288,    344064;
  8: 209952, 1959552,  7838208, 17418240,  23224320,  18579456,   8257536,  1572864;
  9: 708588, 7558272, 35271936, 94058496, 156764160, 167215104, 111476736, 42467328, 7077888;

The row polynomials satisfy (n-1)*P(n,x) = (3*n+4*n*x)*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 12.

P[0, x_] := 0;
P[1, x_] := 12;
P[n_, x_] := P[n, x] = Expand[Together[((3*n + 4*n*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] = 0; v[2] = 12; for(n = 2, N, my(i = n + 1); v[i] = ((3*n + 4*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)

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_A013609 of Triangle read by rows: T(n,k) is the number of ternary words of length n having k runs (i.e., subw…?
    • Geometric basis map (elementary) polytool ? step ›

      • from Triangle read by rows: T(n,k) is the number of ternary words of length n having k levels (n >= 1, 0 <= k <= n-1). A lev…?
        • 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
        • Affine, reversal and Möbius substitutions (elementary) polytool ? step ›

          • from Triangle read by rows: T(n,k) is the number of ternary words of length n having k runs (i.e., subwords of maximal lengt…?
            • 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
            • Affine, reversal and Möbius substitutions (elementary) polytool ? step ›

              • from Triangle read by rows: T(n,k) is the number of ternary words of length n having k levels (n >= 1, 0 <= k <= n-1). A lev…?
                • ↑ Row-hypergeometric rows (multiplier sequences) (above)
                • ↑ Liu–Wang theorem (above)
                • ↑ Iterated real-rootedness preservers (above)
                • ↑ Parent-row provers of polytool (above)
            • Parent-row provers of polytool polytool ? step › direct check
    • Geometric basis map (elementary) polytool ? step ›

      • from Triangle read by rows: T(n,k) is the number of ternary words of length n having k runs (i.e., subwords of maximal lengt…?
        • ↑ Row-hypergeometric rows (multiplier sequences) (above)
        • ↑ Liu–Wang theorem (above)
        • ↑ Iterated real-rootedness preservers (above)
        • ↑ Affine, reversal and Möbius substitutions (elementary) (above)
        • ↑ Parent-row provers of polytool (above)
    • Affine, reversal and Möbius substitutions (elementary) polytool ? step ›

      • from basis_map_A007318 of Triangle read by rows: T(n,k) is the number of ternary words of length n having k levels (n >= 1, …?
        • Geometric basis map (elementary) polytool ? step ›

          • from Triangle read by rows: T(n,k) is the number of ternary words of length n having k levels (n >= 1, 0 <= k <= n-1). A lev…?
            • ↑ Row-hypergeometric rows (multiplier sequences) (above)
            • ↑ Liu–Wang theorem (above)
            • ↑ Iterated real-rootedness preservers (above)
            • ↑ Parent-row provers of polytool (above)
            • ↑ Affine, reversal and Möbius substitutions (elementary) (above)
        • Affine, reversal and Möbius substitutions (elementary) polytool ? step ›

          • from Triangle read by rows: T(n,k) is the number of ternary words of length n having k levels (n >= 1, 0 <= k <= n-1). A lev…?
            • ↑ Row-hypergeometric rows (multiplier sequences) (above)
            • ↑ Liu–Wang theorem (above)
            • ↑ Iterated real-rootedness preservers (above)
            • ↑ Parent-row provers of polytool (above)
            • ↑ Affine, reversal and Möbius substitutions (elementary) (above)

Related ?

Same fingerprint ?

• A027465 → x ↦ x/(x+1)
• A356546 → x ↦ x+1 → basis A013611
• A178821 → basis A013611 → basis A013609
• A038335: Triangle whose (i,j)-th entry is binomial(i,j)*12^(i-j)*9^j.
• A028326 → basis A013611 → basis A013609
• A085880 → x ↦ x+1 → basis A013611
• A003506 → x ↦ x+1 → basis A013611
• A094305 → x ↦ x+1 → basis A013611
• A120909 → basis A013610 → basis A013609
• A038279 → basis A013610 → x ↦ x/(x+1)
• A178820 → basis A013611 → basis A013609
• A038335 → reverse
• basis-map coefficients of A112227 → basis A013610 → basis A007318
• basis-map coefficients of A026729, shifted → basis A013609 → basis A013609
• basis-map coefficients of A030528, shifted → basis A013610 → x ↦ x+1
• A013610 → basis A007318 → D
• A038330 → basis A013610
• A135065 → x ↦ x+1 → basis A013611
• A130123 → basis A013609 → basis A013609
• basis-map coefficients of A026729 → basis A013610 → basis A007318
• A038284 → D
• A038335 → D
• A178820 → basis A007318 → basis A013611
• A027465 → D → basis A013610
• A038329 → basis A013610 → basis A013609
• A120910 → basis A013611
• A013610 → basis A013611 → x ↦ x+1
• A085881 → basis A013611 → basis A013609
• A178821 → basis A007318 → basis A013611
• A038334 → basis A013609 → basis A013610
• A120910 → D → basis A013611
• A013609 → D → basis A013609
• A196347 → basis A013611 → basis A013609
• A038330 → basis A013610 → D
• A013609 → basis A013609 → D
• A038284 → reverse
• A156992 → basis A013611 → basis A013609
• basis-map coefficients of A026729 → basis A013609 → basis A013609
• A085880 → basis A013611 → basis A013609
• A178822 → x ↦ x+1 → basis A013611
• A038221 → basis A013611 → basis A013609
• A130123 → basis A013610 → x ↦ x+1
• A013609 → basis A013609
• Triangle whose (i,j)-th entry is binomial(i,j)*8^(i-j)*6^j.
• A038329 → basis A013611 → basis A013610
• basis-map coefficients of A026729, shifted → basis A013610 → x ↦ x+1
• A038330 → x ↦ x/(x+1)
• A038243 → basis A013609 → x ↦ x/(x+1)
• basis-map coefficients of A030528, shifted → basis A013609 → basis A013609
• A013610 → basis A007318
• A038330 → basis A013610 → reverse
• A196347 → x ↦ x+1 → basis A013611
• basis-map coefficients of A112227 → basis A013609 → basis A013609
• A356546 → basis A013611 → basis A013609
• A136572 → basis A013610 → basis A007318
• A038208 → basis A013611 → basis A013609
• A120910 → basis A013611 → reverse
• A178822 → basis A013611 → basis A013609
• A028326 → basis A007318 → basis A013611

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.