A038325 → θ+1

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(1 + n x\right)\,P_{n}(x) = \left(11 + 22\,x + 11\,x^{2} + 11\,n x + 11\,n x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1112233
2121484363968
31331798611979532426620
41464111712826353823425673205702768
5161051161051048315306442040402627596630618037712
6177156121258732797202451417248801328670756377619612400927453519616
719487171272820394122769177327282039403410254925245538354695487137915589736811224610496
Technical details
Node id
n-a415cf3e2600f94b · 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:         11,          22;
  2:        121,         484,          363;
  3:       1331,        7986,        11979,         5324;
  4:      14641,      117128,       263538,       234256,         73205;
  5:     161051,     1610510,      4831530,      6442040,       4026275,        966306;
  6:    1771561,    21258732,     79720245,    141724880,     132867075,      63776196,      12400927;
  7:   19487171,   272820394,   1227691773,   2728203940,    3410254925,    2455383546,     954871379,    155897368;
  8:  214358881,  3429742096,  18006146004,  48016389344,   75025608350,   72024584016,   42014340676,  13718968384,   1929229929;
  9: 2357947691, 42443058438, 254658350628, 792270424176, 1485507045330, 1782608454396, 1386473242308, 679088935008, 190993762971, 23579476910;
%F Formula
The row polynomials satisfy (1+n*x)*P(n,x) = (11+(11*n+22)*x+(11*n+11)*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[((11 + (11*n + 22)*x + (11*n + 11)*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] = ((11 + (11*n + 22)*x + (11*n + 11)*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.