A038329 → x ↦ x+1 → basis A013609

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(18 + 6\,x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 324 + 216\,x + 36\,x^{2}\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9Pn(1)
032421636576
158325832194421613824
210497613996869984155521296331776
318895683149280209952069984011664077767962624
434012224680244485668704025194240629856083980846656191102976
5612220032142851340814285134087936185602645395205290790458786562799364586471424
61101996057629386561536342843217922285621452895234227202539579392423263232403107841679616110075314176
7198359290368595077871104793437161472617117792256308558896128102852965376228562145283265173504272097792100776962641807540224
Technical details
Node id
n-24c52b8fce7d2d9a · revision 0 · JSON
Definition source
derived:basis_map_A013609
Fingerprint
f6-f9762973ec1089d7

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:            324,             216,              36;
  1:           5832,            5832,            1944,             216;
  2:         104976,          139968,           69984,           15552,            1296;
  3:        1889568,         3149280,         2099520,          699840,          116640,            7776;
  4:       34012224,        68024448,        56687040,        25194240,         6298560,          839808,          46656;
  5:      612220032,      1428513408,      1428513408,       793618560,       264539520,        52907904,        5878656,        279936;
  6:    11019960576,     29386561536,     34284321792,     22856214528,      9523422720,      2539579392,      423263232,      40310784,       1679616;
  7:   198359290368,    595077871104,    793437161472,    617117792256,    308558896128,    102852965376,    22856214528,    3265173504,     272097792,     10077696;
  8:  3570467226624,  11901557422080,  17852336133120,  15868743229440,   9256766883840,   3702706753536,  1028529653760,  195910410240,   24488801280,   1813985280,    60466176;
  9: 64268410079232, 235650836957184, 392751394928640, 392751394928640, 261834263285760, 122189322866688, 40729774288896, 9697565306880, 1616260884480, 179584542720, 11972302848, 362797056;
%F Formula
The row polynomials satisfy P(n,x) = (18+6*x)*P(n-1,x) for n >= 1, with P(0,x) = 324 + 216*x + 36*x^2.
%t Mathematica
P[0, x_] := 324 + 216*x + 36*x^2;
P[n_, x_] := P[n, x] = Expand[(18 + 6*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] = 324 + 216*x + 36*x^2; for(n = 1, N, my(i = n + 1); v[i] = (18 + 6*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.