basis-map coefficients of A112227 → θ+1 → basis A013610

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(1 + n\right)\,P_{n}(x) = \left(2 + 6\,x + n + 3\,n x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 3 + 18\,x + 27\,x^{2}\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9Pn(1)
13182748
2436108108256
35602705404051280
46905401620243014586144
571269453780850510206510328672
681681512756022680408244082417496131072
792162268136085103012247218370815746459049589824
8102703240226801020603061806123607873205904901968302621440
Technical details
Node id
n-49d32d46494ca60e · revision 0 · JSON
Definition source
derived:basis_map_A013610
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 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 = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:  3,  18,   27;
   2:  4,  36,  108,   108;
   3:  5,  60,  270,   540,    405;
   4:  6,  90,  540,  1620,   2430,    1458;
   5:  7, 126,  945,  3780,   8505,   10206,    5103;
   6:  8, 168, 1512,  7560,  22680,   40824,   40824,   17496;
   7:  9, 216, 2268, 13608,  51030,  122472,  183708,  157464,    59049;
   8: 10, 270, 3240, 22680, 102060,  306180,  612360,  787320,   590490,   196830;
   9: 11, 330, 4455, 35640, 187110,  673596, 1683990, 2886840,  3247695,  2165130,  649539;
  10: 12, 396, 5940, 53460, 320760, 1347192, 4041576, 8660520, 12990780, 12990780, 7794468, 2125764;
%F Formula
The row polynomials satisfy (n+1)*P(n,x) = (n+2+(3*n+6)*x)*P(n-1,x) for n >= 2, with P(1,x) = 3 + 18*x + 27*x^2.
%t Mathematica
P[1, x_] := 3 + 18*x + 27*x^2;
P[n_, x_] := P[n, x] = Expand[Together[((n + 2 + (3*n + 6)*x)*P[n - 1, x])/(n + 1)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 3 + 18*x + 27*x^2; for(n = 2, N, my(i = n); v[i] = ((n + 2 + (3*n + 6)*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, v[i])))};
T(10)

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. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.