basis-map coefficients of A021012 → θ+1 → basis A013610

only rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
111
2-2-6-8
36365496
4-24-216-648-648-1536
51201440648012960972030720
6-720-10800-64800-194400-291600-174960-737280
7504090720680400272160061236007348320367416020643840
8-40320-846720-7620480-38102400-114307200-205752960-205752960-88179840-660602880
Technical details
Node id
n-ef3d39adbae9d30c · revision 0 · JSON
Definition source
derived:basis_map_A013610
Fingerprint
f6-f9762973ec1089d7

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): no
  • 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:       -2,        -6;
   3:        6,        36,          54;
   4:      -24,      -216,        -648,        -648;
   5:      120,      1440,        6480,       12960,         9720;
   6:     -720,    -10800,      -64800,     -194400,      -291600,       -174960;
   7:     5040,     90720,      680400,     2721600,      6123600,       7348320,       3674160;
   8:   -40320,   -846720,    -7620480,   -38102400,   -114307200,    -205752960,    -205752960,     -88179840;
   9:   362880,   8709120,    91445760,   548674560,   2057529600,    4938071040,    7407106560,    6348948480,    2380855680;
  10: -3628800, -97977600, -1175731200, -8230118400, -37035532800, -111106598400, -222213196800, -285702681600, -214277011200, -71425670400;
%F Formula
The row polynomials satisfy P(n,x) = -(n+3*n*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[-(n + 3*n*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] = -(n + 3*n*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. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  2. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.