Hadamard-factor parent of A127773 → x ↦ x+1

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(3 + 3\,x\right)\,P_{n-1}(x) + \left(1 + 2\,x + x^{2}\right)\,P_{n-1}'(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1336
212241248
36018018060480
43601440216014403605760
5252012600252002520012600252080640
620160120960302400403200302400120960201601290240
718144012700803810240635040063504003810240127008018144023224320
81814400145152005080320010160640012700800010160640050803200145152001814400464486400
91995840017962560071850240016765056002514758400251475840016765056007185024001796256001995840010218700800
102395008002395008000107775360002874009600050295168000603542016005029516800028740096000107775360002395008000239500800245248819200
1131135104003424861440017124307200051372921600010274584320001438441804800143844180480010274584320005137292160001712430720003424861440031135104006376469299200
12435891456005230697472002876883609600958961203200021576627072000345226033152004027637053440034522603315200215766270720009589612032000287688360960052306974720043589145600178541140377600
13653837184000849988339200050999300352000186997434624000467493586560000841488455808000112198460774400011219846077440008414884558080004674935865600001869974346240005099930035200084998833920006538371840005356234211328000
1410461394944000146459529216000951986939904000380794775961600010471856338944000209437126778880003141556901683200035903507447808000314155690168320002094371267788800010471856338944000380794775961600095198693990400014645952921600010461394944000171399494762496000
Technical details
Node id
n-f365acd4f1e97c97 · revision 0 · JSON
Definition source
derived:shift_x_plus_one
Fingerprint
f6-77a7ed3b1d5f257e

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: 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:        1;
  1:        3,         3;
  2:       12,        24,        12;
  3:       60,       180,       180,         60;
  4:      360,      1440,      2160,       1440,        360;
  5:     2520,     12600,     25200,      25200,      12600,       2520;
  6:    20160,    120960,    302400,     403200,     302400,     120960,      20160;
  7:   181440,   1270080,   3810240,    6350400,    6350400,    3810240,    1270080,    181440;
  8:  1814400,  14515200,  50803200,  101606400,  127008000,  101606400,   50803200,  14515200,   1814400;
  9: 19958400, 179625600, 718502400, 1676505600, 2514758400, 2514758400, 1676505600, 718502400, 179625600, 19958400;
%F Formula
The row polynomials satisfy P(n,x) = (3+3*x)*P(n-1,x) + (1+2*x+x^2)*d/dx 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[(3 + 3*x)*P[n - 1, x] + (1 + 2*x + x^2)*D[P[n - 1, x], 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] = (3 + 3*x)*v[i - 1] + (1 + 2*x + x^2)*deriv(v[i - 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. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.