A258758: Triangle T(n,k) = C(n+k-1,k)*C(2*n-1,n-k).

A258758 ↗ palindromicγ-positivenonnegative coefficientsonly rational roots

Proved for all n all roots real, in (−∞, 0)coefficients of one signHadamard kernelinterlacing (weak)

Recurrence from A258758

\(\left(-n + n^{2}\right)\,P_{n}(x) = \left(2 + 2\,x - 6\,n - 6\,n x + 4\,n^{2} + 4\,n^{2} x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)
\(P_{1}(x) = 1 + x\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1112
236312
31030301080
43514021014035560
5126630126012606301264032
64622772693092406930277246229568
717161201236036600606006036036120121716219648
86435514801801803603604504503603601801805148064351647360
92431021879087516020420403063060306306020420408751602187902431012446720
10923789237804157010110853601939938023279256193993801108536041570109237809237894595072
113527163879876193993805819814011639628016295479216295479211639628058198140193993803879876352716722362368
1213520781622493689237148297457160669278610107084577612493200721070845776669278610297457160892371481622493613520785538111488
135200300676039004056234001487285800371821450066927861008923714800892371480066927861003718214500148728580040562340067603900520030042600857600
142005830028081620018253053007301221200200783583004015671660060235074900688400856006023507490040156716600200783583007301221200182530530028081620020058300328635187200
Technical details
Node id
n-9a3e4fcd8c6a0286 · revision 1 · JSON
Definition source
oeis_catalog:A258758
Fingerprint
f6-77a7ed3b1d5f257e

Observed on the stored rows ?

  • Degrees: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 (affine: slope 1, intercept 0)
  • Palindromic rows: yes
  • γ-positive (gamma_positive): yes
  • Nonnegative coefficients (nonn): yes
  • Only rational roots (rr_by_factors: every nonzero row is a product of linear factors over ℚ): yes

Matches ?

  • A258758 triangle 44 terms, 8 rows · tabl · nonn · catalog b-file?
  • A258758 reversed triangle 44 terms, 8 rows · tabl · nonn · catalog b-file?

Row sums ? A069723

Submission text ?

Atlas rows n = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:     1;
  1:     1,      1;
  2:     3,      6,      3;
  3:    10,     30,     30,      10;
  4:    35,    140,    210,     140,      35;
  5:   126,    630,   1260,    1260,     630,     126;
  6:   462,   2772,   6930,    9240,    6930,    2772,     462;
  7:  1716,  12012,  36036,   60060,   60060,   36036,   12012,   1716;
  8:  6435,  51480, 180180,  360360,  450450,  360360,  180180,  51480,   6435;
  9: 24310, 218790, 875160, 2042040, 3063060, 3063060, 2042040, 875160, 218790, 24310;
%F Formula
The row polynomials satisfy (n^2-n)*P(n,x) = (4*n^2-6*n+2+(4*n^2-6*n+2)*x)*P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 1 + x.
%t Mathematica
P[0, x_] := 1;
P[1, x_] := 1 + x;
P[n_, x_] := P[n, x] = Expand[Together[((4*n^2 - 6*n + 2 + (4*n^2 - 6*n + 2)*x)*P[n - 1, x])/(n^2 - n)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; v[2] = 1 + x; for(n = 2, N, my(i = n + 1); v[i] = ((4*n^2 - 6*n + 2 + (4*n^2 - 6*n + 2)*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)

polytool c48629374597

A258758 triangle, offset 0, from P0
%e Example
Triangle begins:
  0:     1;
  1:     1,      1;
  2:     3,      6,      3;
  3:    10,     30,     30,      10;
  4:    35,    140,    210,     140,      35;
  5:   126,    630,   1260,    1260,     630,     126;
  6:   462,   2772,   6930,    9240,    6930,    2772,     462;
  7:  1716,  12012,  36036,   60060,   60060,   36036,   12012,   1716;
  8:  6435,  51480, 180180,  360360,  450450,  360360,  180180,  51480,   6435;
  9: 24310, 218790, 875160, 2042040, 3063060, 3063060, 2042040, 875160, 218790, 24310;
%F Formula
The row polynomials satisfy (n^2-n)*P(n,x) = (4*n^2-6*n+2+(4*n^2-6*n+2)*x)*P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 1 + x.
%t Mathematica
P[0, x_] := 1;
P[1, x_] := 1 + x;
P[n_, x_] := P[n, x] = Expand[Together[((4*n^2 - 6*n + 2 + (4*n^2 - 6*n + 2)*x)*P[n - 1, x])/(n^2 - n)]];
Table[PadRight[CoefficientList[P[n, x], x], n + 1], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; v[2] = 1 + x; for(n = 2, N, my(i = n + 1); v[i] = ((4*n^2 - 6*n + 2 + (4*n^2 - 6*n + 2)*x)*v[i - 1])/(n^2 - n)); v};
row(n, p) = {my(c = Vecrev(p)); c = concat(c, vector(n + 1 - #c)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i - 1, v[i])))};
T(9)

polytool c48629374597

A258758 reversed triangle, offset 0, from P0
%e Example
Triangle begins:
  0:     1;
  1:     1,      1;
  2:     3,      6,      3;
  3:    10,     30,     30,      10;
  4:    35,    140,    210,     140,      35;
  5:   126,    630,   1260,    1260,     630,     126;
  6:   462,   2772,   6930,    9240,    6930,    2772,     462;
  7:  1716,  12012,  36036,   60060,   60060,   36036,   12012,   1716;
  8:  6435,  51480, 180180,  360360,  450450,  360360,  180180,  51480,   6435;
  9: 24310, 218790, 875160, 2042040, 3063060, 3063060, 2042040, 875160, 218790, 24310;
%F Formula
Row n lists the coefficients of P(n,x) in descending powers of x, where (n^2-n)*P(n,x) = (4*n^2-6*n+2+(4*n^2-6*n+2)*x)*P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 1 + x.
%t Mathematica
P[0, x_] := 1;
P[1, x_] := 1 + x;
P[n_, x_] := P[n, x] = Expand[Together[((4*n^2 - 6*n + 2 + (4*n^2 - 6*n + 2)*x)*P[n - 1, x])/(n^2 - n)]];
Table[Reverse[PadRight[CoefficientList[P[n, x], x], n + 1]], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; v[2] = 1 + x; for(n = 2, N, my(i = n + 1); v[i] = ((4*n^2 - 6*n + 2 + (4*n^2 - 6*n + 2)*x)*v[i - 1])/(n^2 - n)); v};
row(n, p) = {my(c = Vecrev(p)); c = concat(c, vector(n + 1 - #c)); c = Vecrev(c); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i - 1, v[i])))};
T(9)

polytool c48629374597

Properties

Proof chains ? JSON

Same fingerprint ?

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.