A038329 → basis A013611 → x ↦ x+1

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in (−∞, −1]coefficients of one signHadamard kernelinterlacing (weak)

Recurrence

\(P_{n}(x) = \left(27 + 12\,x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 729 + 648\,x + 144\,x^{2}\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9Pn(1)
07296481441521
1196832624411664172859319
2531441944784629856186624207362313441
314348907318864602834352012597120279936024883290224199
4387420489103312130411479125606802444802267481604031078429859843518743761
51046035320332543321076433910947683214155168014285134080380936908856435097635831808137231006679
62824295364811004193907488156207941164813885150325767713972403202742745743366094990540877396705284299816965352009260481
77625597484987305023899399485422647100435256234858819328374899058795521666218039091249369423380489403699691521044855521285159780352208728361158759
Technical details
Node id
n-2591f30de7dbadc3 · revision 0 · JSON
Definition source
derived:shift_x_plus_one
Fingerprint
f6-12e1fe8c90bb4450

Observed on the stored rows ?

  • Degrees: 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 (affine: slope 1, intercept 2)
  • 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:              729,               648,               144;
  1:            19683,             26244,             11664,              1728;
  2:           531441,            944784,            629856,            186624,             20736;
  3:         14348907,          31886460,          28343520,          12597120,           2799360,            248832;
  4:        387420489,        1033121304,        1147912560,         680244480,         226748160,          40310784,           2985984;
  5:      10460353203,       32543321076,       43391094768,       32141551680,       14285134080,        3809369088,         564350976,         35831808;
  6:     282429536481,     1004193907488,     1562079411648,     1388515032576,      771397240320,      274274574336,       60949905408,       7739670528,        429981696;
  7:    7625597484987,    30502389939948,    54226471004352,    56234858819328,    37489905879552,    16662180390912,     4936942338048,     940369969152,     104485552128,      5159780352;
  8:  205891132094649,   915071698198440,  1830143396396880,  2169058840174080,  1687045764579840,   899757741109248,   333243607818240,   84633297223680,   14105549537280,   1393140695040,    61917364224;
  9: 5559060566555523, 27177629436493668, 60394732081097040, 80526309441462720, 71578941725744640, 44538008184907776, 19794670304403456, 6284022318858240, 1396449404190720, 206881393213440, 18389457174528, 743008370688;
%F Formula
The row polynomials satisfy P(n,x) = (27+12*x)*P(n-1,x) for n >= 1, with P(0,x) = 729 + 648*x + 144*x^2.
%t Mathematica
P[0, x_] := 729 + 648*x + 144*x^2;
P[n_, x_] := P[n, x] = Expand[(27 + 12*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 729 + 648*x + 144*x^2; for(n = 1, N, my(i = n + 1); v[i] = (27 + 12*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

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.