A085881 → basis A013611 → x ↦ x/(x+1)

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in [−1, 0]coefficients of one signHadamard kernel

Recurrence

\(\left(1 + x\right)\,P_{n}(x) = \left(-2 - 8\,x - 6\,x^{2} + 4\,n + 16\,n x + 12\,n x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1268
21272108192
31201080324032407680
416802016090720181440136080430080
5302404536002721600816480012247200734832030965760
666528011975040898128003592512008083152009699782404849891202724986880
71729728036324288032691859201634592960049037788800882680198408826801984037829151360283398635520
85189184001245404160013076743680078460462080029422673280007061441587200105921623808009078996326400340462362240034007836262400
9176432256004763670912005716405094400400148356608001800667604736005402002814208001080400562841600138908643793920010418148284544003472716094848004625065731686400
10670442572800201132771840002715292419840002172233935872000114042281633280004105522138798080010263805346995200017595094880563200019794481740633600013196321160422400039588963481267200703009991216332800
11281585880576009292334059008001393850108851200012544650979660800075267905877964800031612520468745216009483756140623564800203223345870504960003048350188057574400030483501880575744000182901011283454464004988209398639667200118105678524343910400
121295295050649600466306218233856007694052600858624007694052600858624000519348550557957120002492873042678194176008725055649373679616002243585738410374758400420672325951945267200056089643460259368960005048067911423343206400275349158804909629440068837289701227407360021731444848479279513600
13647647525324800002525825348766720000454648562778009600005001134190558105600003750850642918579200000202545934717603276800008101837388704131072000024305512166112393216000054687402373752884736000091145670622921474560000010937480474750576947200008948847661159562956800004474423830579781478400001032559345518411110400004346288969695855902720000
1434972966367539200001468864587436646400002864285945501460480000343714313460175257600002835643086046445875200001701385851627867525120000765623633232540386304000026249953139401384673280000689061269909286347673600001378122539818572695347200002067183809727859043020800002255109610612209865113600001691332207959157398835200007806148652119187994624000016727461397398259988480000938798417454304874987520000
Technical details
Node id
n-1215f894ba61b32e · revision 0 · JSON
Definition source
derived:mobius_x_over_x_plus_one
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 0)
  • 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:           1;
  1:           2,            6;
  2:          12,           72,           108;
  3:         120,         1080,          3240,           3240;
  4:        1680,        20160,         90720,         181440,          136080;
  5:       30240,       453600,       2721600,        8164800,        12247200,         7348320;
  6:      665280,     11975040,      89812800,      359251200,       808315200,       969978240,        484989120;
  7:    17297280,    363242880,    3269185920,    16345929600,     49037788800,     88268019840,      88268019840,      37829151360;
  8:   518918400,  12454041600,  130767436800,   784604620800,   2942267328000,   7061441587200,   10592162380800,    9078996326400,    3404623622400;
  9: 17643225600, 476367091200, 5716405094400, 40014835660800, 180066760473600, 540200281420800, 1080400562841600, 1389086437939200, 1041814828454400, 347271609484800;
%F Formula
The row polynomials satisfy (1+x)*P(n,x) = (4*n-2+(16*n-8)*x+(12*n-6)*x^2)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((4*n - 2 + (16*n - 8)*x + (12*n - 6)*x^2)*P[n - 1, x])/(1 + x)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = ((4*n - 2 + (16*n - 8)*x + (12*n - 6)*x^2)*v[i - 1])/(1 + x)); 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.