A028326 → basis A007318 → basis A013609

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(3 + 2\,x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 2\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
022
16410
21824850
3541087216250
4162432432192321250
5486162021601440480646250
614585832972086404320115212831250
7437420412408244536030240120962688256156250
8131226998416329621772818144096768322566144512781250
939366236196629856979776979776653184290304829441382410243906250
101180987873202361960419904048988803919104217728082944020736030720204819531250
1135429425981568660520173210402309472021555072143700486842880228096050688067584409697656250
12106288285030563117787269284160103926240110854656862202884926873620528640608256012165121474568192488281250
1331886462763493211053972827020822445034704054041644848037017632024678416012339259304960158146562875392319488163842441406250
149565938892820883868890481031704128189145756825219434242521943424192148070411208637444981616641660538884025548867092486881283276812207031250
Technical details
Node id
n-2b21a809f4a82963 · revision 0 · JSON
Definition source
derived:reversal
Fingerprint
f6-f06e51c139cfae05

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:     6,      4;
  2:    18,     24,      8;
  3:    54,    108,     72,     16;
  4:   162,    432,    432,    192,     32;
  5:   486,   1620,   2160,   1440,    480,     64;
  6:  1458,   5832,   9720,   8640,   4320,   1152,    128;
  7:  4374,  20412,  40824,  45360,  30240,  12096,   2688,   256;
  8: 13122,  69984, 163296, 217728, 181440,  96768,  32256,  6144,   512;
  9: 39366, 236196, 629856, 979776, 979776, 653184, 290304, 82944, 13824, 1024;
%F Formula
The row polynomials satisfy P(n,x) = (3+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[(3 + 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] = (3 + 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.