A124860 → basis A013611

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(8 + 32\,x + 32\,x^{2}\right)\,P_{n-2}(x) + \left(2 + 4\,x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)
\(P_{1}(x) = 2 + 4\,x\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1246
2124848108
3402404803201080
4176140842245632281614256
5672672026880537605376021504163296
62752330241651204403206604805283841761282006208
7108801523209139203046400609280073113604874240139264023794560
8437767004164902912196116484902912078446592784465924482662411206656287214336
9174592314265625141248117325824351977472703954944938606592804519936402259968893911043436494336
1069939213987840125890560671416320234995712056398970889399828480107426611208056995840358088704071617740841298398208
11279552061501440615014400369008640014760345600413289676808265793536011808276480011808276480078721843200314887372805725224960495217981440
121118617626846822429531504641968766976088594513920283502444544661505703936113400977817614175122227201260010864640756006518784274911461376458185768965944792559616
13447365121163149312139577917441023571394565117856972801842428510208491314269388898262853877761473942808166416377142312960131017138503687146389372928238212979097636648150630471324450021376
14178962432501094809665142325248521138601984286626231091211465049243648343951477309447861748052787213758059092377618344078789836818344078789836813341148210790466705741053952205248434012162932120485888855971764420608
Technical details
Node id
n-5ed6981065d6360f · revision 0 · JSON
Definition source
derived:basis_map_A013611
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:      2,       4;
  2:     12,      48,       48;
  3:     40,     240,      480,       320;
  4:    176,    1408,     4224,      5632,      2816;
  5:    672,    6720,    26880,     53760,     53760,     21504;
  6:   2752,   33024,   165120,    440320,    660480,    528384,    176128;
  7:  10880,  152320,   913920,   3046400,   6092800,   7311360,   4874240,   1392640;
  8:  43776,  700416,  4902912,  19611648,  49029120,  78446592,  78446592,  44826624,  11206656;
  9: 174592, 3142656, 25141248, 117325824, 351977472, 703954944, 938606592, 804519936, 402259968, 89391104;
%F Formula
The row polynomials satisfy P(n,x) = (8+32*x+32*x^2)*P(n-2,x) + (2+4*x)*P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 2 + 4*x.
%t Mathematica
P[0, x_] := 1;
P[1, x_] := 2 + 4*x;
P[n_, x_] := P[n, x] = Expand[(8 + 32*x + 32*x^2)*P[n - 2, x] + (2 + 4*x)*P[n - 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; v[2] = 2 + 4*x; for(n = 2, N, my(i = n + 1); v[i] = (8 + 32*x + 32*x^2)*v[i - 2] + (2 + 4*x)*v[i - 1]); 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. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  2. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.