A290319 → x ↦ x+1 → reverse
nonnegative coefficientsonly rational roots
Proved for all n all roots real, in (−∞, 0]coefficients of one signHadamard kernel
Recurrence
\(P_{n}(x) = \left(1 - 2\,x + 4\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)
Rows ?
| n | x0 | x1 | x2 | x3 | x4 | x5 | x6 | x7 | Pn(1) |
|---|---|---|---|---|---|---|---|---|---|
| 0 | 1 | 1 | |||||||
| 1 | 1 | 2 | 3 | ||||||
| 2 | 1 | 8 | 12 | 21 | |||||
| 3 | 1 | 18 | 92 | 120 | 231 | ||||
| 4 | 1 | 32 | 344 | 1408 | 1680 | 3465 | |||
| 5 | 1 | 50 | 920 | 7600 | 27024 | 30240 | 65835 | ||
| 6 | 1 | 72 | 2020 | 27840 | 194224 | 624768 | 665280 | 1514205 | |
| 7 | 1 | 98 | 3892 | 80360 | 918064 | 5674592 | 16909248 | 17297280 | 40883535 |
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Technical details
- Node id
n-b1607adc23dda083· revision 0 · JSON- Definition source
derived:reversal- Fingerprint
f6-68e273231fc13fce
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: no
- γ-positive (gamma_positive): no
- Nonnegative coefficients (
nonn): yes - Only rational roots (
rr_by_factors: every nonzero row is a product of linear factors over ℚ): yes
Matches ?
No OEIS matches.
Submission text ?
Atlas rows n = 0, …, ascending powers of x
%e ExampleTriangle begins: 0: 1; 1: 1, 2; 2: 1, 8, 12; 3: 1, 18, 92, 120; 4: 1, 32, 344, 1408, 1680; 5: 1, 50, 920, 7600, 27024, 30240; 6: 1, 72, 2020, 27840, 194224, 624768, 665280; 7: 1, 98, 3892, 80360, 918064, 5674592, 16909248, 17297280; 8: 1, 128, 6832, 197120, 3328864, 33216512, 187147008, 524574720, 518918400; 9: 1, 162, 11184, 429408, 10030944, 146397888, 1316508416, 6887572992, 18354458880, 17643225600;
%F FormulaThe row polynomials satisfy P(n,x) = (1+(4*n-2)*x)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t MathematicaP[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[(1 + (4*n - 2)*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten%o PARI/GPP(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = (1 + (4*n - 2)*x)*v[i - 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)polytool c48629374597
Properties
- Real-rooted? Every row P_n, n ≥ 0, is zero or real-rooted with all roots in (−∞, 0]
- Coefficients of one sign? Every nonzero row, n ≥ 0: the coefficients of P_n have one sign
- Hadamard kernel (Malo)? Rows P_n, n ≥ 0, are Hadamard kernels (preserve real-rootedness)
Proof chains ? JSON
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Affine, reversal and Möbius substitutions (elementary) polytool ? step ›
Related ?
Same fingerprint ?
References
- [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
- [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
- [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
- [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.