A136572 → (θ+1)² → basis A013609

nonnegative coefficientsonly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
14812
2187272162
39657611527682592
460048001440019200960048600
54320432001728003456003456001382401049760
6352804233602116800564480084672006773760225792025719120
73225604515840270950409031680018063360021676032014450688041287680705438720
Technical details
Node id
n-a4124af3cb94889c · revision 0 · JSON
Definition source
derived:basis_map_A013609
Fingerprint
f6-11aec07ce60b6d61

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:       18,        72,         72;
  3:       96,       576,       1152,         768;
  4:      600,      4800,      14400,       19200,        9600;
  5:     4320,     43200,     172800,      345600,      345600,       138240;
  6:    35280,    423360,    2116800,     5644800,     8467200,      6773760,      2257920;
  7:   322560,   4515840,   27095040,    90316800,   180633600,    216760320,    144506880,     41287680;
  8:  3265920,  52254720,  365783040,  1463132160,  3657830400,   5852528640,   5852528640,   3344302080,   836075520;
  9: 36288000, 653184000, 5225472000, 24385536000, 73156608000, 146313216000, 195084288000, 167215104000, 83607552000, 18579456000;
%F Formula
The row polynomials satisfy n*P(n,x) = (n^2+2*n+1+(2*n^2+4*n+2)*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 + (2*n^2 + 4*n + 2)*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 + (2*n^2 + 4*n + 2)*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.