A156992 → basis A013609 → θ+1

nonnegative coefficientsonly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
14812
2249672192
3192115217287683840
41920153603456030720960092160
5230402304006912009216005760001382402580480
6322560387072014515200258048002419200011612160225792082575360
7516096072253440325140480722534400903168000650280960252887040412876802972712960
89289728014863564807803371520208089907203251404800031213486080182078668805945425920836075520118908518400
9185794560033443020800200658124800624269721600117050572800014046068736001092472012800535088332800150493593600185794560005231974809600
104087480320081749606400055180984320001961990553600042918543360000618027024384006008596070400039239811072000165542952960004087480320000449622835200251134790860800
1198099527680021581896089600161864220672000647456882688000161864220672000027193189072896003172538725171200258982753075200014567779860480005395474022400001187004284928001177194332160013059009124761600
12255058771968006121410527232005050163684966400224451719331840006312704606208000012120392843919360016497201370890240016160523791892480011362868291174400056112929832960000185172668448768003672846316339200331576403558400731304510986649600
13714164561510400185682785992704001671145073934336008170042583678976002553138307399680000551477874398330880085785447128629248009804051100414771200827216811597496320051062766147993600002246761710511718400668458029573734400120693810895257600999830386114560043878270659198976000
1421424936845312000599898231668736000584900775877017600031194708046774272000107231808910786560000257356341385887744000450373597425303552000588243066024886272000579051768118247424000428927235643146240000235909979603730432000935841241403228160002534570028800409600041992876216811520003213740526796800002808209322188734464000
Technical details
Node id
n-25474d00a8e4fbc9 · revision 0 · JSON
Definition source
derived:theta_plus_one
Fingerprint
f6-e99c3824c4864868

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:          4,           8;
  2:         24,          96,           72;
  3:        192,        1152,         1728,          768;
  4:       1920,       15360,        34560,        30720,          9600;
  5:      23040,      230400,       691200,       921600,        576000,        138240;
  6:     322560,     3870720,     14515200,     25804800,      24192000,      11612160,       2257920;
  7:    5160960,    72253440,    325140480,    722534400,     903168000,     650280960,     252887040,     41287680;
  8:   92897280,  1486356480,   7803371520,  20808990720,   32514048000,   31213486080,   18207866880,   5945425920,    836075520;
  9: 1857945600, 33443020800, 200658124800, 624269721600, 1170505728000, 1404606873600, 1092472012800, 535088332800, 150493593600, 18579456000;
%F Formula
The row polynomials satisfy (1+n*x)*P(n,x) = (2*n+2+(2*n^2+6*n+4)*x+(2*n^2+4*n+2)*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[((2*n + 2 + (2*n^2 + 6*n + 4)*x + (2*n^2 + 4*n + 2)*x^2)*P[n - 1, x])/(1 + n*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] = ((2*n + 2 + (2*n^2 + 6*n + 4)*x + (2*n^2 + 4*n + 2)*x^2)*v[i - 1])/(1 + n*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.