A136572 → (θ+1)² → basis A007318

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1448
218361872
39628828896768
46002400360024006009600
54320216004320043200216004320138240
635280211680529200705600529200211680352802257920
73225602257920677376011289600112896006773760225792032256041287680
83265920261273609144576018289152022861440018289152091445760261273603265920836075520
9362880003265920001306368000304819200045722880004572288000304819200013063680003265920003628800018579456000
1043908480043908480001975881600052690176000922078080001106493696009220780800052690176000197588160004390848000439084800449622835200
11574801920063228211200316141056000948423168000189684633600026555848704002655584870400189684633600094842316800031614105600063228211200574801920011771943321600
1280951270400971415244800534278384640017809279488000400708788480006411340615680074798973849600641134061568004007087884800017809279488000534278384640097141524480080951270400331576403558400
13122049607680015866448998400951986939904003490618779648008726546949120001570778450841600209437126778880020943712677888001570778450841600872654694912000349061877964800951986939904001586644899840012204960768009998303861145600
141961511552000027461161728000017849755123200007139902049280000196347306355200003926946127104000058904191906560000673190764646400005890419190656000039269461271040000196347306355200007139902049280000178497551232000027461161728000019615115520000321374052679680000
Technical details
Node id
n-420ccc1e2c1f9612 · 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:        4,         4;
  2:       18,        36,         18;
  3:       96,       288,        288,         96;
  4:      600,      2400,       3600,       2400,        600;
  5:     4320,     21600,      43200,      43200,      21600,       4320;
  6:    35280,    211680,     529200,     705600,     529200,     211680,      35280;
  7:   322560,   2257920,    6773760,   11289600,   11289600,    6773760,    2257920,     322560;
  8:  3265920,  26127360,   91445760,  182891520,  228614400,  182891520,   91445760,   26127360,   3265920;
  9: 36288000, 326592000, 1306368000, 3048192000, 4572288000, 4572288000, 3048192000, 1306368000, 326592000, 36288000;
%F Formula
The row polynomials satisfy n*P(n,x) = (n^2+2*n+1+(n^2+2*n+1)*x)*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[((n^2 + 2*n + 1 + (n^2 + 2*n + 1)*x)*P[n - 1, x])/(n)]];
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] = ((n^2 + 2*n + 1 + (n^2 + 2*n + 1)*x)*v[i - 1])/(n)); 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.