basis-map coefficients of A026729, shifted → basis A007318 → (θ+1)²

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

Recurrence

\(\left(1 - 4\,x + x^{2} + 3\,n x - 2\,n x^{2} + n^{2} x^{2}\right)\,P_{n}(x) = \left(-1 + x^{2} - 3\,n x - 3\,n x^{2} - n^{2} x^{2} - n^{2} x^{3}\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
111
2-1-4-5
318918
4-1-12-27-16-56
5116546425160
6-1-20-90-160-125-36-432
7124135320375216491120
8-1-28-189-560-875-756-343-64-2816
9132252896175020161372512816912
10-1-36-324-1344-3150-4536-4116-2304-729-100-16640
111404051920525090721029076803645100012139424
12-1-44-495-2640-8250-16632-22638-21120-13365-5500-1331-144-92160
13148594352012375285124527650688400952200079861728169212992
14-1-52-702-4576-17875-46332-84084-109824-104247-71500-34606-11232-2197-196-487424
1515681958242502572072147147219648243243200200121121524161537927442251105920
Technical details
Node id
n-02083e8fdf8aee31 · revision 0 · JSON
Definition source
derived:theta_plus_one_squared
Fingerprint
f6-d42e6339eab21b9c

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): no

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:  1;
   2: -1,  -4;
   3:  1,   8,    9;
   4: -1, -12,  -27,   -16;
   5:  1,  16,   54,    64,    25;
   6: -1, -20,  -90,  -160,  -125,   -36;
   7:  1,  24,  135,   320,   375,   216,    49;
   8: -1, -28, -189,  -560,  -875,  -756,  -343,   -64;
   9:  1,  32,  252,   896,  1750,  2016,  1372,   512,   81;
  10: -1, -36, -324, -1344, -3150, -4536, -4116, -2304, -729, -100;
%F Formula
The row polynomials satisfy (1+(3*n-4)*x+(n^2-2*n+1)*x^2)*P(n,x) = -(1+3*n*x+(n^2+3*n-1)*x^2+n^2*x^3)*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[Together[(-(1 + 3*n*x + (n^2 + 3*n - 1)*x^2 + n^2*x^3)*P[n - 1, x])/(1 + (3*n - 4)*x + (n^2 - 2*n + 1)*x^2)]];
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] = (-(1 + 3*n*x + (n^2 + 3*n - 1)*x^2 + n^2*x^3)*v[i - 1])/(1 + (3*n - 4)*x + (n^2 - 2*n + 1)*x^2)); 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.