A258758 → basis A013610

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Submission text ?

Triangle begins:
  0:        1;
  1:        2,         3;
  2:       12,        36,         27;
  3:       80,       360,        540,        270;
  4:      560,      3360,       7560,       7560,       2835;
  5:     4032,     30240,      90720,     136080,     102060,       30618;
  6:    29568,    266112,     997920,    1995840,    2245320,     1347192,      336798;
  7:   219648,   2306304,   10378368,   25945920,   38918880,    35026992,    17513496,    3752892;
  8:  1647360,  19768320,  103783680,  311351040,  583783200,   700539840,   525404880,  225173520,   42220035;
  9: 12446720, 168030720, 1008184320, 3528645120, 7939451520, 11909177280, 11909177280, 7655899680, 2870962380, 478493730;

The row polynomials satisfy (n^2-n)*P(n,x) = (8*n^2-12*n+4+(12*n^2-18*n+6)*x)*P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 2 + 3*x.

P[0, x_] := 1;
P[1, x_] := 2 + 3*x;
P[n_, x_] := P[n, x] = Expand[Together[((8*n^2 - 12*n + 4 + (12*n^2 - 18*n + 6)*x)*P[n - 1, x])/(n^2 - n)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten

P(N) = {my(v = vector(N + 1)); v[1] = 1; v[2] = 2 + 3*x; for(n = 2, N, my(i = n + 1); v[i] = ((8*n^2 - 12*n + 4 + (12*n^2 - 18*n + 6)*x)*v[i - 1])/(n^2 - n)); 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)
• 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 Triangle T(n,k) = C(n+k-1,k)*C(2*n-1,n-k).?
    • 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 ?

• A085880 → basis A013610 → reverse
• A178822 → basis A013609 → basis A013610
• A178821 → basis A013610 → D
• basis-map coefficients of A026729 → basis A013610 → basis A013609
• A134346 → basis A013610
• A178822 → basis A013611 → basis A007318
• A003506 → D → basis A013610
• A038243 → basis A013611
• basis-map coefficients of A112227 → basis A013609 → x ↦ x+1
• A038330 → basis A013611 → basis A013610
• A028326 → basis A013610 → D
• A356546 → basis A013609 → basis A013610
• basis-map coefficients of A026729, shifted → basis A013610 → basis A013609
• A013620 → D
• A038338 → basis A013610 → reverse
• A156992 → basis A013611 → x ↦ x+1
• A038221 → basis A013610 → D
• A120910 → basis A013609 → reverse
• A038338 → basis A013610 → D
• A135838 → basis A013610
• A216973 → basis A013610
• A085881 → basis A007318 → basis A013609
• basis-map coefficients of A113214, shifted → basis A013610
• A038208 → D → basis A013610
• basis-map coefficients of A026729 → basis A013609 → x ↦ x+1
• A038221 → basis A013611 → x ↦ x+1
• A178821 → basis A013610
• A085880 → basis A013609 → basis A013610
• Triangle whose (i,j)-th entry is binomial(i,j)*12^(i-j)*8^j.
• A028326 → basis A013610
• A027466 → basis A013611 → x ↦ x/(x+1)
• A178820 → basis A013611 → basis A007318
• A085881 → basis A013610
• A178821 → basis A013609 → basis A013610
• A196347 → basis A013611 → x ↦ x+1
• A038334 → D
• A038330 → basis A013609 → basis A013609
• A038325 → basis A013610
• A120910 → basis A013609
• A085881 → basis A013609 → basis A013610
• A085880 → basis A013610
• A178822 → basis A013610 → D
• basis-map coefficients of A026729, shifted → basis A007318 → basis A013610
• A136572 → basis A013609 → x ↦ x+1
• A178820 → basis A013609 → basis A013610
• A156992 → basis A013610
• A135065 → x ↦ x+1 → x ↦ x/(x+1)
• basis-map coefficients of A112227 → basis A013610 → basis A013609
• A124860 → basis A013610
• A356546 → basis A013610
• A120909 → basis A013610 → x ↦ x+1
• A120910 → x ↦ x/(x+1)
• A038325 → basis A013609 → basis A013610
• basis-map coefficients of A026729, shifted → basis A013609 → basis A007318
• A135089 → basis A013610
• A038325 → basis A007318 → basis A013609
• A120910 → D → basis A013609
• A178821 → basis A013610 → reverse
• A136572 → basis A013610 → basis A013609
• basis-map coefficients of A112227 → x ↦ x+1 → basis A013610
• A376827 → basis A013610
• A038330 → basis A013609 → x ↦ x/(x+1)
• A131431 → x ↦ x+1 → basis A013610
• A028326 → basis A007318 → basis A013609
• A038221 → basis A013610
• A085880 → D → basis A013610
• A013610 → basis A013611 → basis A013609
• A178820 → basis A007318 → basis A013609
• A038338 → basis A013609 → basis A013610
• A094305 → basis A013610
• basis-map coefficients of A026729 → basis A007318 → basis A013610
• A028326 → basis A013611 → x ↦ x+1
• A003506 → x ↦ x+1 → basis A013609
• A094305 → x ↦ x+1 → x ↦ x/(x+1)
• A038291 → basis A013609 → basis A013611
• A344565 → basis A013610
• A013620: Triangle of coefficients in expansion of (2+3x)^n.
• A178820 → basis A013610
• A178820 → basis A013610 → D
• A196347 → basis A013610
• A028326 → basis A013609 → basis A013610
• A085880 → basis A013611 → x ↦ x+1
• A085880 → basis A013610 → D
• A038334 → reverse
• A356546 → x ↦ x+1 → basis A013609
• basis-map coefficients of A113214, shifted → D → basis A013610
• A038338 → basis A013610
• basis-map coefficients of A030528, shifted → basis A013610 → basis A013609
• A178821 → basis A013611 → basis A007318
• A038220 → D
• A013610 → D → basis A013609
• A356546 → basis A013611 → basis A007318
• A038328 → basis A013609 → basis A013610
• A120910 → basis A013610 → basis A013610
• basis-map coefficients of A127647 → basis A013610
• A196347 → basis A013610 → D
• A134058 → basis A013610
• A038208 → basis A013610 → D
• basis-map coefficients of A030528, shifted → basis A013609 → x ↦ x+1
• A156992 → basis A013610 → D
• A038221 → basis A013609 → basis A013610
• A038208 → basis A013610
• A156992 → basis A007318 → basis A013609
• A132200 → basis A013610
• A135065 → x ↦ x+1 → basis A013609
• A156992 → basis A013609 → basis A013610
• A120910 → basis A013609 → D
• A085881 → basis A013611 → basis A007318
• A178822 → x ↦ x+1 → basis A013609
• A094305 → x ↦ x+1 → basis A013609
• A038243 → basis A013611 → D
• A027465 → basis A013611 → basis A013610
• A134059 → basis A013610
• A135065 → basis A013610
• A038220: Triangle whose (i,j)-th entry is binomial(i,j)*3^(i-j)*2^j.
• A178822 → basis A013610
• A013609 → basis A013610 → x ↦ x+1
• A028326 → D → 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.