A156992 → x ↦ x/(x+1)

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in [−1, 0]coefficients of one signHadamard kernel

Recurrence

\(\left(1 + x\right)\,P_{n}(x) = \left(1 + 3\,x + 2\,x^{2} + n + 3\,n x + 2\,n x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1246
26242454
324144288192648
41209602880384019209720
5720720028800576005760023040174960
650406048030240080640012096009676803225603674160
740320564480338688011289600225792002709504018063360516096088179840
8362880580608040642560162570240406425600650280960650280960371589120928972802380855680
9362880065318400522547200243855360073156608001463132160019508428800167215104008360755200185794560071425670400
1039916800798336000718502400038320128000134120448000321889075200536481792000613122048000459841536000204374016000408748032002357047123200
11479001600105380352001053803520006322821120002529128448000708155965440014163119308800202330275840002023302758400013488685056000539547402240098099527680084853696435200
12622702080014944849920016439334912001095955660800049318004736000157817615155200368241102028800631270460620800789088075776000701411622912000420846973747200153035263180800255058771968003309294160972800
13871782912002266635571200271996268544001994639302656009973196513280003590350744780800957426865274880019148537305497600287228059582464003191422884249600025531383073996800139262089494528004642069649817600714164561510400138990354760857600
1413076743680003661488230400047599346995200038079477596160002094371267788800083774850711552000251324552134656000574456119164928000100529820853862400013403976113848320001340397611384832000974834626461696000487417313230848000149974557917184000214249368453120006254565964238592000
Technical details
Node id
n-4c8e9ad9dc69215d · revision 0 · JSON
Definition source
derived:mobius_x_over_x_plus_one
Fingerprint
f6-11aec07ce60b6d61

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 Example
Triangle begins:
  0:       1;
  1:       2,        4;
  2:       6,       24,        24;
  3:      24,      144,       288,        192;
  4:     120,      960,      2880,       3840,       1920;
  5:     720,     7200,     28800,      57600,      57600,       23040;
  6:    5040,    60480,    302400,     806400,    1209600,      967680,      322560;
  7:   40320,   564480,   3386880,   11289600,   22579200,    27095040,    18063360,     5160960;
  8:  362880,  5806080,  40642560,  162570240,  406425600,   650280960,   650280960,   371589120,   92897280;
  9: 3628800, 65318400, 522547200, 2438553600, 7315660800, 14631321600, 19508428800, 16721510400, 8360755200, 1857945600;
%F Formula
The row polynomials satisfy (1+x)*P(n,x) = (n+1+(3*n+3)*x+(2*n+2)*x^2)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((n + 1 + (3*n + 3)*x + (2*n + 2)*x^2)*P[n - 1, x])/(1 + x)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = ((n + 1 + (3*n + 3)*x + (2*n + 2)*x^2)*v[i - 1])/(1 + x)); 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

Proof chains ? JSON

Candidate equalities ?

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.