basis-map coefficients of A127647 → basis A013611

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(4 + 16\,x + 16\,x^{2}\right)\,P_{n-2}(x) + \left(2 + 4\,x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)
\(P_{1}(x) = 2 + 4\,x\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1246
28323272
324144288192648
4806401920256012806480
52562560102402048020480819262208
683299844992013312019968015974453248606528
72688376322257927526401505280180633612042243440645878656
887041392649748483899392974848015597568155975688912896222822457106944
928160506880405504018923520567705601135411201513881601297612806488064014417920554273280
109113618227201640448087490560306216960734920704122486784013998489601049886720466616320933232645381489664
1129491264880646488064038928384015571353604359979008871995801612457082880124570828808304721920332188876860397977652242776064
12954368229048322519531521679687680755859456024187502592564375060489675001036812093751296010750001152064500006912234545479683909091328507190284288
1330883848029798496357580870662225923533111296012719200665633917868441667835736883210175360532481130595614720904476491776493350813696164450271232253000417284923881644032
149994240279838720363790336029103226880160067747840640270991360192081297408043904296550407683251896320102443358617601024433586176074504260812803725213040640114621939712016374562816047802140098560
Technical details
Node id
n-8dd53223cceac8df · 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:     8,     32,      32;
  3:    24,    144,     288,      192;
  4:    80,    640,    1920,     2560,     1280;
  5:   256,   2560,   10240,    20480,    20480,      8192;
  6:   832,   9984,   49920,   133120,   199680,    159744,     53248;
  7:  2688,  37632,  225792,   752640,  1505280,   1806336,   1204224,    344064;
  8:  8704, 139264,  974848,  3899392,  9748480,  15597568,  15597568,   8912896,  2228224;
  9: 28160, 506880, 4055040, 18923520, 56770560, 113541120, 151388160, 129761280, 64880640, 14417920;
%F Formula
The row polynomials satisfy P(n,x) = (4+16*x+16*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[(4 + 16*x + 16*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] = (4 + 16*x + 16*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.