basis-map coefficients of A026729 → (θ+1)² → basis A013611

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Triangle begins:
   1:   1;
   2:   4,   16;
   3:   9,   72,   144;
   4:  16,  192,   768,   1024;
   5:  25,  400,  2400,   6400,    6400;
   6:  36,  720,  5760,  23040,   46080,    36864;
   7:  49, 1176, 11760,  62720,  188160,   301056,   200704;
   8:  64, 1792, 21504, 143360,  573440,  1376256,  1835008,  1048576;
   9:  81, 2592, 36288, 290304, 1451520,  4644864,  9289728, 10616832,  5308416;
  10: 100, 3600, 57600, 537600, 3225600, 12902400, 34406400, 58982400, 58982400, 26214400;

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

P[1, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((n^2 + 4*n^2*x)*P[n - 1, x])/(n^2 - 2*n + 1)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten

P(N) = {my(v = vector(N)); v[1] = 1; for(n = 2, N, my(i = n); v[i] = ((n^2 + 4*n^2*x)*v[i - 1])/(n^2 - 2*n + 1)); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i, v[i])))};
T(10)

Properties

• Real-rooted? Every row P_n, n ≥ 1, is zero or real-rooted with all roots in (−∞, 0]
  by Geometric basis map (elementary)
• Coefficients of one sign? Every nonzero row, n ≥ 1: the coefficients of P_n have one sign
  derived from Geometric basis map (elementary)
• Hadamard kernel (Malo)? Rows P_n, n ≥ 1, are Hadamard kernels (preserve real-rootedness)
  derived from Geometric basis map (elementary)
• Interlacing of consecutive rows? Rows P_(m-1), P_m interlace (weak, unordered) for every m ≥ 2
  by Geometric basis map (elementary)

Proof chains ? JSON

• Geometric basis map (elementary) polytool ? step ›

  • from theta_plus_one_squared of basis-map coefficients of Square array of binomial coefficients T(n,k) = binomial(n,k), n >= …?
    • Laguerre’s theorem on multiplier sequences [SP14; Bra15, Thm 7.1 of arXiv:1410.6601] polytool ? step ›

      • from basis-map coefficients of Square array of binomial coefficients T(n,k) = binomial(n,k), n >= 0, k >= 0, read by downwar…?
        • 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 basis-map coefficients of Square array of binomial coefficients T(n,k) = binomial(n,k), n >= 0, k >= 0, read by downwar…?
            • ↑ Iterated real-rootedness preservers (above)
            • ↑ Parent-row provers of polytool (above)
    • Affine, reversal and Möbius substitutions (elementary) polytool ? step ›

      • from theta_plus_one_squared of basis-map coefficients of Square array of binomial coefficients T(n,k) = binomial(n,k), n >= …?
        • ↑ Laguerre’s theorem on multiplier sequences (above)

Related ?

Same fingerprint ?

• A131436 → basis A013611
• A130123 → basis A013611
• basis-map coefficients of A112227 → basis A013611
• A038231: Triangle whose (i,j)-th entry is binomial(i,j)*4^(i-j).
• basis-map coefficients of A026729 → basis A013611 → reverse
• basis-map coefficients of A112227 → basis A013611 → D
• A038330 → basis A007318
• image under θ+1 → (θ+1)² → basis A013611
• A038329 → reverse
• image under θ+1 → basis A013611
• A131431 → θ+1 → basis A013611
• A130123 → D → basis A013611
• basis-map coefficients of A030528, shifted → basis A013611
• A038231 → D
• basis-map coefficients of A030528, shifted → (θ+1)² → basis A013611
• A027467 → basis A013611
• basis-map coefficients of A026729 → basis A013611 → D
• A136521 → basis A013611
• A131431 → D → basis A013611
• A120910 → basis A007318 → basis A007318
• A131431 → basis A013611
• A027467 → basis A013611 → reverse
• basis-map coefficients of A026729, shifted → D → basis A013611
• basis-map coefficients of A112227 → basis A013611 → reverse
• A136572 → (θ+1)² → basis A013611
• A127648 → D → basis A013611
• A136572 → basis A013611 → reverse
• A136572 → θ+1 → basis A013611
• basis-map coefficients of A026729, shifted → basis A013611
• basis-map coefficients of A026729, shifted → θ+1 → basis A013611
• A013611 → D → D
• A013611 → D
• A038329 → D
• A136572 → basis A013611
• basis-map coefficients of A112227 → (θ+1)² → basis A013611
• A132440 → θ+1 → basis A013611
• image under θ+1 → θ+1 → D → basis A013611
• A130123 → (θ+1)² → basis A013611
• basis-map coefficients of A021012 → θ+1 → basis A013611
• basis-map coefficients of A030528, shifted → θ+1 → basis A013611
• A130123 → θ+1 → basis A013611
• A013611: Triangle of coefficients in expansion of (1+4x)^n.
• Triangle whose (i,j)-th entry is binomial(i,j)*12^(i-j)*3^j.
• A027467 → basis A013611 → D
• A136572 → D → basis A013611
• basis-map coefficients of A026729 → basis A013611
• basis-map coefficients of A030528, shifted → D → basis A013611
• basis-map coefficients of A112227 → θ+1 → basis A013611
• A038303 → basis A007318 → basis A013610
• A013610 → basis A013611 → x ↦ x/(x+1)
• A130123 → basis A013611 → D
• A038330 → basis A007318 → reverse
• A027466 → basis A013609 → D
• basis-map coefficients of A026729, shifted → (θ+1)² → basis A013611
• A038330 → basis A007318 → D
• basis-map coefficients of A026729 → D → basis A013611
• A027466 → basis A013609
• A132440 → basis A013611
• A129186 → basis A013611
• A038231 → D → D
• A136572 → basis A013611 → D
• basis-map coefficients of A021012 → basis A013611
• A134309 → 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. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.