A156992 → basis A007318 → D

nonnegative coefficientsonly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
122
2241236
328828872648
438405760288048012960
55760011520086400288003600291600
6967680241920024192001209600302400302407348320
718063360541900806773760045158400169344003386880282240205752960
83715891201300561920195084288016257024008128512002438553604064256029030406348948480
983607552003344302080058525286400585252864003657830400014631321600365783040052254720032659200214277011200
102043740160009196830720001839366144000214592716800016094453760008047226880002682408960005748019200071850240003991680007856823744000
11539547402240026977370112000606990827520008093211033600070815596544000424893579264001770389913600050582568960009484231680001053803520005269017600311130220262400
1215303526318080084169394749440021042348687360003156352303104000315635230310400022094466121728001104723306086400394544037888000986360094720001643933491200016439334912007472424960013237176643891200
1346420696498176002785241789890560076594149221990400127656915369984000143614029791232000114891223832985600670198805692416002872280595824640089758768619520001994639302656000299195895398400271996268544001133317785600602291537297049600
141499745579171840009748346264616960002924503879385088000536159044553932800067019880569241600006031789251231744000402119283415449600020105964170772480007539736564039680002094371267788800004188742535577600057119216394240004759934699520001830744115200029187974499780096000
Technical details
Node id
n-df90e6e2770b9985 · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-11aec07ce60b6d61

Observed on the stored rows ?

  • Degrees: -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 (affine: slope 1, intercept -1)
  • 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:          0;
  1:          2;
  2:         24,          12;
  3:        288,         288,          72;
  4:       3840,        5760,        2880,         480;
  5:      57600,      115200,       86400,       28800,        3600;
  6:     967680,     2419200,     2419200,     1209600,      302400,       30240;
  7:   18063360,    54190080,    67737600,    45158400,    16934400,     3386880,     282240;
  8:  371589120,  1300561920,  1950842880,  1625702400,   812851200,   243855360,   40642560,   2903040;
  9: 8360755200, 33443020800, 58525286400, 58525286400, 36578304000, 14631321600, 3657830400, 522547200, 32659200;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = (2*n^2+2*n+(n^2+n)*x)*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 2.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 2;
P[n_, x_] := P[n, x] = Expand[Together[((2*n^2 + 2*n + (n^2 + n)*x)*P[n - 1, x])/(n - 1)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 0; v[2] = 2; for(n = 2, N, my(i = n + 1); v[i] = ((2*n^2 + 2*n + (n^2 + n)*x)*v[i - 1])/(n - 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

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.