A178820 → basis A013609 → D

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-1 + n\right)\,P_{n}(x) = \left(6 + 6\,x + 2\,n + 2\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 8\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
188
28080160
34809604801920
4224067206720224017920
589603584053760358408960143360
632256161280322560322560161280322561032192
71075206451201612800215040016128006451201075206881280
83379202365440709632011827200118272007096320236544033792043253760
910137608110080283852805677056070963200567705602838528081100801013760259522560
102928640263577601054310402460057603690086403690086402460057601054310402635776029286401499463680
118200192820019203690086409840230401722040320206644838417220403209840230403690086408200192082001928396996608
122236416024600576012300288003690086400738017280010332241920103322419207380172800369008640012300288002460057602236416045801799680
1359637760715653120393609216013120307200295206912004723310592055105290240472331059202952069120013120307200393609216071565312059637760244276264960
1415597568020276838401216610304044609044480111522611200200740700160267654266880267654266880200740700160111522611200446090444801216610304020276838401559756801277752770560
Technical details
Node id
n-cf30426e4e63a8f1 · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-77a7ed3b1d5f257e

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: yes
  • γ-positive (gamma_positive): yes
  • 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:       8;
  2:      80,      80;
  3:     480,     960,      480;
  4:    2240,    6720,     6720,     2240;
  5:    8960,   35840,    53760,    35840,     8960;
  6:   32256,  161280,   322560,   322560,   161280,    32256;
  7:  107520,  645120,  1612800,  2150400,  1612800,   645120,   107520;
  8:  337920, 2365440,  7096320, 11827200, 11827200,  7096320,  2365440,  337920;
  9: 1013760, 8110080, 28385280, 56770560, 70963200, 56770560, 28385280, 8110080, 1013760;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = (2*n+6+(2*n+6)*x)*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 8.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 8;
P[n_, x_] := P[n, x] = Expand[Together[((2*n + 6 + (2*n + 6)*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] = 8; for(n = 2, N, my(i = n + 1); v[i] = ((2*n + 6 + (2*n + 6)*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.