A156992 → basis A013611 → x ↦ x/(x+1)

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in [−1, 0]coefficients of one signHadamard kernel

Recurrence

\(\left(1 + x\right)\,P_{n}(x) = \left(2 + 8\,x + 6\,x^{2} + 2\,n + 8\,n x + 6\,n x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
141216
224144216384
319217285184518412288
4192023040103680207360155520491520
523040345600207360062208009331200559872023592960
63225605806080435456001741824003919104004702924802351462401321205760
7516096010838016097542144048771072001463132160026336378880263363788801128701952084557168640
Technical details
Node id
n-da6dc42b60c5086d · revision 0 · JSON
Definition source
derived:mobius_x_over_x_plus_one
Fingerprint
f6-f9762973ec1089d7

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:          1;
  1:          4,          12;
  2:         24,         144,          216;
  3:        192,        1728,         5184,          5184;
  4:       1920,       23040,       103680,        207360,         155520;
  5:      23040,      345600,      2073600,       6220800,        9331200,        5598720;
  6:     322560,     5806080,     43545600,     174182400,      391910400,      470292480,       235146240;
  7:    5160960,   108380160,    975421440,    4877107200,    14631321600,    26336378880,     26336378880,     11287019520;
  8:   92897280,  2229534720,  23410114560,  140460687360,   526727577600,  1264146186240,   1896219279360,   1625330810880,    609499054080;
  9: 1857945600, 50164531200, 601974374400, 4213820620800, 18962192793600, 56886578380800, 113773156761600, 146279772979200, 109709829734400, 36569943244800;
%F Formula
The row polynomials satisfy (1+x)*P(n,x) = (2*n+2+(8*n+8)*x+(6*n+6)*x^2)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((2*n + 2 + (8*n + 8)*x + (6*n + 6)*x^2)*P[n - 1, x])/(1 + x)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = ((2*n + 2 + (8*n + 8)*x + (6*n + 6)*x^2)*v[i - 1])/(1 + x)); 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.