basis-map coefficients of A026729 → 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

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
111
2325
3912425
42754368125
5812162169616625
62438101080720240323125
772929164860432021605766415625
82187102062041222680151206048134412878125
9656134992816481088649072048384161283072256390625
10196831180983149284898884898883265921451524147269125121953125
1159049393660118098020995202449440195955210886404147201036801536010249765625
12177147129907843302608660520115473601077753671850243421440114048025344033792204848828125
135314414251528155889363464208051963120554273284311014424634368102643203041280608256737284096244140625
141594323138174665526986413510411222517352027020822424018508816012339280061696296524807907328143769615974481921220703125
154782969446410441934445245158520649457287841260971712126097171296074035256043187224908083283026944201277443354624344064163846103515625
Technical details
Node id
n-60d5bc5c6c128acb · revision 0 · JSON
Definition source
derived:shift_x_plus_one
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 -1)
  • 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 = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:     1;
   2:     3,      2;
   3:     9,     12,      4;
   4:    27,     54,     36,      8;
   5:    81,    216,    216,     96,     16;
   6:   243,    810,   1080,    720,    240,     32;
   7:   729,   2916,   4860,   4320,   2160,    576,     64;
   8:  2187,  10206,  20412,  22680,  15120,   6048,   1344,   128;
   9:  6561,  34992,  81648, 108864,  90720,  48384,  16128,  3072,  256;
  10: 19683, 118098, 314928, 489888, 489888, 326592, 145152, 41472, 6912, 512;
%F Formula
The row polynomials satisfy P(n,x) = (3+2*x)*P(n-1,x) for n >= 2, with P(1,x) = 1.
%t Mathematica
P[1, x_] := 1;
P[n_, x_] := P[n, x] = Expand[(3 + 2*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 1; for(n = 2, N, my(i = n); 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, v[i])))};
T(10)

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. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.