A038325 → basis A013609 → θ+1

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(1 + n x\right)\,P_{n}(x) = \left(22 + 44\,x + 22\,x^{2} + 22\,n x + 22\,n x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1224466
2484193614523872
310648638889583242592212960
4234256187404842166083748096117128011244288
551536325153632015460896020614528012884080030921792577206784
61133799041360558848510209568090703923208503492800408167654479365932829025255424
7249435788834921010432157144546944349210104320436512630400314289093888122223536512199548631041436750143488
Technical details
Node id
n-2359edb2d01f321b · revision 0 · JSON
Definition source
derived:theta_plus_one
Fingerprint
f6-e99c3824c4864868

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:            22,             44;
  2:           484,           1936,            1452;
  3:         10648,          63888,           95832,           42592;
  4:        234256,        1874048,         4216608,         3748096,         1171280;
  5:       5153632,       51536320,       154608960,       206145280,       128840800,        30921792;
  6:     113379904,     1360558848,      5102095680,      9070392320,      8503492800,      4081676544,       793659328;
  7:    2494357888,    34921010432,    157144546944,    349210104320,    436512630400,    314289093888,    122223536512,     19954863104;
  8:   54875873536,   878013976576,   4609573377024,  12292195672064,  19206555737600,  18438293508096,  10755671213056,   3512055906304,   493882861824;
  9: 1207269217792, 21730845920256, 130385075521536, 405642457178112, 760579607208960, 912695528650752, 709874300061696, 347693534724096, 97788806641152, 12072692177920;
%F Formula
The row polynomials satisfy (1+n*x)*P(n,x) = (22+(22*n+44)*x+(22*n+22)*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[((22 + (22*n + 44)*x + (22*n + 22)*x^2)*P[n - 1, x])/(1 + n*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] = ((22 + (22*n + 44)*x + (22*n + 22)*x^2)*v[i - 1])/(1 + n*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.