basis-map coefficients of A021012 → Veronese 2 → θ+1
palindromicγ-positivenonnegative coefficientsonly rational roots
Proved for all n all roots real, in (−∞, 0]coefficients of one signHadamard kernel
Recurrence
\(P_{n}(x) = \left(-2\,x - n x + n^{2} x\right)\,P_{n-2}(x)\)
\(P_{1}(x) = 1\)
\(P_{2}(x) = 0\)
Rows ?
| n | x0 | x1 | x2 | x3 | Pn(1) |
|---|---|---|---|---|---|
| 1 | 1 | 1 | |||
| 2 | 0 | ||||
| 3 | 0 | 4 | 4 | ||
| 4 | 0 | ||||
| 5 | 0 | 0 | 72 | 72 | |
| 6 | 0 | ||||
| 7 | 0 | 0 | 0 | 2880 | 2880 |
| 8 | 0 |
Compute more
?
Technical details
- Node id
n-7220b7345604de85· revision 0 · JSON- Definition source
derived:theta_plus_one- Fingerprint
f6-1641c37dbfc60bc3
Observed on the stored rows ?
- Degrees: 0, -1, 1, -1, 2, -1, 3, -1, 4, -1, 5, -1, 6, -1, 7 (half affine: slope 1, intercept -1)
- 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 ?
No OEIS matches.
Submission text ?
Atlas rows n = 1, …, ascending powers of x
%e ExampleTriangle begins: 1: 1; 2: 0; 3: 0, 4; 4: 0; 5: 0, 0, 72; 6: 0; 7: 0, 0, 0, 2880; 8: 0; 9: 0, 0, 0, 0, 201600; 10: 0;
%F FormulaThe row polynomials satisfy P(n,x) = (n^2-n-2)*x*P(n-2,x) for n >= 3, with P(1,x) = 1, P(2,x) = 0.
%t MathematicaP[1, x_] := 1;
P[2, x_] := 0;
P[n_, x_] := P[n, x] = Expand[(n^2 - n - 2)*x*P[n - 2, x]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten%o PARI/GPP(N) = {my(v = vector(N)); v[1] = 1; v[2] = 0; for(n = 3, N, my(i = n); v[i] = (n^2 - n - 2)*x*v[i - 2]); 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)polytool c48629374597
Properties
- Real-rooted? Every row P_n, n ≥ 1, is zero or real-rooted with all roots in (−∞, 0]
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Coefficients of one sign?
Every nonzero row, n ≥ 1: the coefficients of P_n have one sign
derived from Laguerre’s theorem on multiplier sequences
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Hadamard kernel (Malo)?
Rows P_n, n ≥ 1, are Hadamard kernels (preserve real-rootedness)
derived from Laguerre’s theorem on multiplier sequences
Proof chains ? JSON
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Laguerre’s theorem on multiplier sequences [SP14; Bra15, Thm 7.1 of arXiv:1410.6601] polytool ? step ›
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from
veronese_section_2_0 of basis-map coefficients of Triangle of coefficients in expansion of x^n in terms of Laguerre pol…?
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Veronese sections of Pólya frequency sequences [ASW52; Edr53; AW24] polytool ? step ›
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from
basis-map coefficients of Triangle of coefficients in expansion of x^n in terms of Laguerre polynomials L_n(x).?
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Affine, reversal and Möbius substitutions (elementary) polytool ? step ›
- ↑ Affine, reversal and Möbius substitutions (elementary) (above)
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from
basis-map coefficients of Triangle of coefficients in expansion of x^n in terms of Laguerre polynomials L_n(x).?
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from
veronese_section_2_0 of basis-map coefficients of Triangle of coefficients in expansion of x^n in terms of Laguerre pol…?
Related ?
Same fingerprint ?
- A127648 → Veronese 2 → D
- basis-map coefficients of A026729, shifted → Veronese 2
- A131431 → Veronese 2 (j=1)
- A003982: veronese_section_2_0 of basis-map coefficients of Triangle read by rows: T(n,k) = binomial(k,n-k). shifted by …
- A023531 → Veronese 2 → θ+1
- basis-map coefficients of A026729, shifted → Veronese 2 (j=1)
- basis-map coefficients of A030528, shifted → Veronese 2 (j=1)
- A136572 → Veronese 2
- A127648 → Veronese 2 (j=1) → D
- A130123 → Veronese 2 → (θ+1)²
- basis-map coefficients of A021012 → Veronese 2 → D
- A127648 → Veronese 2
- basis-map coefficients of A112227 → Veronese 2
- A136572 → Veronese 2 (j=1) → θ+1
- A136572 → Veronese 2 (j=1)
- A127648 → Veronese 2 → θ+1
- A136572 → Veronese 2 (j=1) → D
- A136572 → Veronese 2 → (θ+1)²
- A133080 → Veronese 2 (j=1)
- A136572 → Veronese 2 → θ+1
- basis-map coefficients of A021012 → Veronese 2 → (θ+1)²
- basis-map coefficients of A026729 → Veronese 2 (j=1)
- A127648 → Veronese 2 (j=1) → θ+1
- A130123 → Veronese 2 (j=1) → θ+1
- A136572 → Veronese 2 → D
- A127648 → Veronese 2 → (θ+1)²
- A130123 → Veronese 2 (j=1)
- A130123 → Veronese 2 (j=1) → (θ+1)²
- A130123 → Veronese 2 → D
- basis-map coefficients of A021012 → Veronese 2
- A130123 → Veronese 2
- A023531 → Veronese 2 → (θ+1)²
- A130123 → Veronese 2 (j=1) → D
- A023531 → Veronese 2 → D
- A131431 → Veronese 2
- A127648 → Veronese 2 (j=1) → (θ+1)²
- A130123 → Veronese 2 → θ+1
- A127648 → Veronese 2 (j=1)
- basis-map coefficients of A021012 → Veronese 2 (j=1)
- A136572 → Veronese 2 (j=1) → (θ+1)²
References
- [ASW52] Michael Aissen, I. J. Schoenberg and A. M. Whitney. On the generating functions of totally positive sequences I. Journal d’Analyse Mathématique, 2(1):93–103, 1952. doi:10.1007/BF02786970
- [AW24] Christos A. Athanasiadis and David G. Wagner. Veronese sections and interlacing matrices of polynomials and formal power series. arXiv:2404.12989. arXiv
- [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
- [Edr53] Albert Edrei. Proof of a Conjecture of Schoenberg on the Generating Function of a Totally Positive Sequence. Canadian Journal of Mathematics, 5:86–94, 1953. doi:10.4153/CJM-1953-010-3
- [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.