A085880 → basis A013611 → D

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-2\,n + n^{2}\right)\,P_{n}(x) = \left(12 + 24\,x - 20\,n - 40\,n x + 8\,n^{2} + 16\,n^{2} x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 0\)
\(P_{2}(x) = 4\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
10
244
3326496
42409609602160
5179210752215041433648384
6134401075203225604300802150401088640
71013761013760405504081100808110080324403224634368
876876892252164612608012300288018450432014760345649201152560431872
9585728082001920492011520164003840032800768003936092160262406144074973184012809871360
10448081927169310725018517504200740700165018517504080296280064802962800644588358860811470897152293986547712
113439820806191677440495334195202311559577606934678732801386935746560184924766208015850694246407925347123201761188249606770599280640
122648662016529732403204767591628802542715535360889950437376021358810497024355980174950404068344856576030512586424320135611495219202712229904384156400843382784
1320448411648449865056256449865056256026991903375360107967613501440302309317804032604618635608064863740908011520863740908011520575827272007680230330908803072418783470551043622374778208256
1415823175680037975621632004177318379520027848789196800012531955138560004010225644339200935719317012480016040902577356800200511282216960001782322508595200010693935051571200388870365511680064811727585280084090843065548800
151226904698880318995221708803827942660505602807157951037440140357897551872005052884311867392013474358164979712026948716329959424040423074494939136044914527216599040035931621773279232019599066421788672065330221405962240100508032932249601956082380232458240
Technical details
Node id
n-c3c16d1eee30ac4f · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-11aec07ce60b6d61

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 -2)
  • 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:        0;
   2:        4;
   3:       32,        64;
   4:      240,       960,        960;
   5:     1792,     10752,      21504,       14336;
   6:    13440,    107520,     322560,      430080,      215040;
   7:   101376,   1013760,    4055040,     8110080,     8110080,     3244032;
   8:   768768,   9225216,   46126080,   123002880,   184504320,   147603456,    49201152;
   9:  5857280,  82001920,  492011520,  1640038400,  3280076800,  3936092160,  2624061440,   749731840;
  10: 44808192, 716931072, 5018517504, 20074070016, 50185175040, 80296280064, 80296280064, 45883588608, 11470897152;
%F Formula
The row polynomials satisfy (n^2-2*n)*P(n,x) = (8*n^2-20*n+12+(16*n^2-40*n+24)*x)*P(n-1,x) for n >= 3, with P(1,x) = 0, P(2,x) = 4.
%t Mathematica
P[1, x_] := 0;
P[2, x_] := 4;
P[n_, x_] := P[n, x] = Expand[Together[((8*n^2 - 20*n + 12 + (16*n^2 - 40*n + 24)*x)*P[n - 1, x])/(n^2 - 2*n)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 0; v[2] = 4; for(n = 3, N, my(i = n); v[i] = ((8*n^2 - 20*n + 12 + (16*n^2 - 40*n + 24)*x)*v[i - 1])/(n^2 - 2*n)); 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. [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.