A178820 → basis A013610 → D

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-1 + n\right)\,P_{n}(x) = \left(6 + 9\,x + 2\,n + 3\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 12\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
11212
2120180300
3720216016204500
4336015120226801134052500
5134408064018144018144068040525000
6483843628801088640163296012247203674164725000
71612801451520544320010886400122472007348320183708039375000
8506880532224023950080598752008981280080831520404157608660520309375000
915206401824768095800320287400960538876800646652160484989120207852480389723402320312500
1043929605930496035582976012454041602802159360420323904042032390402702082240101328084016888014016757812500
11123002881845043201245404160498161664013076743680235381386242942267328025219434240141859317604728643920709296588117304687500
12335462405535129604151347200186810624005604318720011769069312017653603968018914575680014185931760070929658800212788976402901667860799804687500
1389456640161021952013284311040664215552002241727488005380145971209415255449601210532843520113487454080075658302720034046236224092853371520116066714405332031250000
1423396352045622886404106059776022583328768084687482880022865620377604573124075520685968611328077171468774406430955731200385857343872015785073158403946268289604553386488034863281250000
Technical details
Node id
n-5d099c0cb73e3d94 · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-f06e51c139cfae05

Observed on the stored rows ?

  • Degrees: -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 (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 = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:       0;
  1:      12;
  2:     120,      180;
  3:     720,     2160,     1620;
  4:    3360,    15120,    22680,     11340;
  5:   13440,    80640,   181440,    181440,     68040;
  6:   48384,   362880,  1088640,   1632960,   1224720,    367416;
  7:  161280,  1451520,  5443200,  10886400,  12247200,   7348320,   1837080;
  8:  506880,  5322240, 23950080,  59875200,  89812800,  80831520,  40415760,   8660520;
  9: 1520640, 18247680, 95800320, 287400960, 538876800, 646652160, 484989120, 207852480, 38972340;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = (2*n+6+(3*n+9)*x)*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 12.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 12;
P[n_, x_] := P[n, x] = Expand[Together[((2*n + 6 + (3*n + 9)*x)*P[n - 1, x])/(n - 1)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 0; v[2] = 12; for(n = 2, N, my(i = n + 1); v[i] = ((2*n + 6 + (3*n + 9)*x)*v[i - 1])/(n - 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.