A120909 → basis A013610 → basis A013610

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(9 + 18\,x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 3\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
033
1275481
22439729722187
3218713122262441749659049
4196831574644723926298563149281594323
5177147177147070858801417176014171760566870443046721
6159432319131876956593802550916803826375203061100161020366721162261467
71434890720088469812053081884017693960803538792096424655046428310336183666009631381059609
Technical details
Node id
n-ada652e4c7cffb11 · revision 0 · JSON
Definition source
derived:basis_map_A013610
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:          3;
  1:         27,          54;
  2:        243,         972,          972;
  3:       2187,       13122,        26244,        17496;
  4:      19683,      157464,       472392,       629856,        314928;
  5:     177147,     1771470,      7085880,     14171760,      14171760,       5668704;
  6:    1594323,    19131876,     95659380,    255091680,     382637520,     306110016,     102036672;
  7:   14348907,   200884698,   1205308188,   4017693960,    8035387920,    9642465504,    6428310336,    1836660096;
  8:  129140163,  2066242608,  14463698256,  57854793024,  144636982560,  231419172096,  231419172096,  132239526912,   33059881728;
  9: 1162261467, 20920706406, 167365651248, 781039705824, 2343119117472, 4686238234944, 6248317646592, 5355700839936, 2677850419968, 595077871104;
%F Formula
The row polynomials satisfy P(n,x) = (9+18*x)*P(n-1,x) for n >= 1, with P(0,x) = 3.
%t Mathematica
P[0, x_] := 3;
P[n_, x_] := P[n, x] = Expand[(9 + 18*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] = 3; for(n = 1, N, my(i = n + 1); v[i] = (9 + 18*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.