A028326 → basis A013609 → x ↦ x+1

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in (−∞, −1]coefficients of one signHadamard kernelinterlacing (weak)

Recurrence

\(P_{n}(x) = \left(4 + 2\,x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 2\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
022
18412
23232872
31281929616432
45121024768256322592
520485120512025606406415552
681922457630720204807680153612893312
73276811468817203214336071680215043584256559872
81310725242889175049175045734402293765734481925123359232
95242882359296471859255050244128768206438468812814745618432102420155392
102097152104857602359296031457280275251201651507268812801966080368640409602048120932352
1183886084613734411534336017301504017301504012111052860555264216268805406720901120901124096725594112
123355443220132659255364812892274688010380902408304721924844421122076180486488064014417920216268819660881924353564672
131342177288724152322617245696479828377659978547205398069248359871283217993564166747586561874329603748659251118084259841638426121388032
14536870912375809638412213813248244276264963358798643233587986432251909898241439485132862977474562099249152524812288954204161192755291750432768156728328192
Technical details
Node id
n-6a307f0d4f22d81e · revision 0 · JSON
Definition source
derived:shift_x_plus_one
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:      2;
  1:      8,       4;
  2:     32,      32,       8;
  3:    128,     192,      96,      16;
  4:    512,    1024,     768,     256,      32;
  5:   2048,    5120,    5120,    2560,     640,      64;
  6:   8192,   24576,   30720,   20480,    7680,    1536,    128;
  7:  32768,  114688,  172032,  143360,   71680,   21504,   3584,    256;
  8: 131072,  524288,  917504,  917504,  573440,  229376,  57344,   8192,   512;
  9: 524288, 2359296, 4718592, 5505024, 4128768, 2064384, 688128, 147456, 18432, 1024;
%F Formula
The row polynomials satisfy P(n,x) = (4+2*x)*P(n-1,x) for n >= 1, with P(0,x) = 2.
%t Mathematica
P[0, x_] := 2;
P[n_, x_] := P[n, x] = Expand[(4 + 2*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] = 2; for(n = 1, N, my(i = n + 1); v[i] = (4 + 2*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.