A046716 → basis A013611

OEIS matches ?

• A094869: row sums, 15 terms agree OEIS nonn (row-sum match: finite agreement only) · view at the OEIS · generated b-file 200 terms from n = 0 ?

A generated b-file is computed from the node's definition along the row alignment of its OEIS link and starts at the entry's offset. It is an identification on a finite prefix, not a proof that the node and the OEIS entry agree for every n.

OEIS submission text ?

Fields to paste into an OEIS submission: the example %e, the formula %F and programs %t (Mathematica) and %o (PARI/GP) that list the same rows. For an OEIS link the row numbers, the offset and the orientation are those of the entry, as matched; the matched terms were compared with the published ones, which identifies the node with the entry on a finite prefix, not for every n. The PARI/GP program is not machine-checked here.

Triangle begins:
   1:      1;
   2:      2,        4;
   3:      5,       20,        16;
   4:     16,      100,       176,         64;
   5:     65,      576,      1712,       1792,        256;
   6:    326,     3844,     16864,      32704,      24064,        1024;
   7:   1957,    29252,    173504,     510144,     743424,      431104,        4096;
   8:  13700,   250100,   1890096,    7564544,   16898304,    19963904,     9744384,       16384;
   9: 109601,  2374944,  21942240,  112000512,  340945664,   618635264,   619110400,   263454720,      65536;
  10: 986410, 24817476, 272039616, 1696430464, 6580225536, 16250932224, 24943345664, 21743370240, 8236695552, 262144;

The row polynomials satisfy P(n,x) = -(n-2+(8*n-16)*x+(16*n-32)*x^2)*P(n-2,x) + (n+(4*n-4)*x)*P(n-1,x) for n >= 3, with P(1,x) = 1, P(2,x) = 2 + 4*x.

P[1, x_] := 1;
P[2, x_] := 2 + 4*x;
P[n_, x_] := P[n, x] = Expand[-(n - 2 + (8*n - 16)*x + (16*n - 32)*x^2)*P[n - 2, x] + (n + (4*n - 4)*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten

P(N) = {my(v = vector(N)); v[1] = 1; v[2] = 2 + 4*x; for(n = 3, N, my(i = n); v[i] = -(n - 2 + (8*n - 16)*x + (16*n - 32)*x^2)*v[i - 2] + (n + (4*n - 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, v[i])))};
T(10)

Proved properties

• Real-rooted. Every row P_n, n >= 1, is zero or real-rooted with all roots in (-inf, 0]
  Every polynomial of the sequence has only real roots, inside the stated interval.
  by the cited steps: e-5274dd88a300ad29
• Coefficients of one sign. Every nonzero row, n >= 1: the coefficients of P_n have one sign
  All coefficients of each polynomial have the same sign (after x -> -x when alternating).
  derived from the cited steps by a stated theorem: e-5274dd88a300ad29
• Hadamard kernel (Malo). Rows P_n, n >= 1, are Hadamard kernels (preserve real-rootedness)
  Multiplying the coefficients of any real-rooted polynomial termwise by those of a row (Hadamard product) gives a real-rooted polynomial again.
  derived from the cited steps by a stated theorem: e-5274dd88a300ad29
• Interlacing of consecutive rows. Rows P_(m-1), P_m interlace (weak, unordered) for every m >= 2
  The roots of consecutive polynomials alternate on the real line.
  by the cited steps: e-5274dd88a300ad29

Proof chains

1 incoming proof step. Each step is expanded back to the roots of the proof DAG, the theorem checks of a node's own rule. JSON

• basis_map A013611 e-5274dd88a300ad29

  Geometric basis map (elementary) polytool ?

  • premise (sequence): Coefficients of a special case of Poisson-Charlier polynomials.
    uses: Every row P_n, n >= 1, is zero or real-rooted with all roots in (-inf, 0]
    • theorem_check three_term_recurrence e-3fcbce34648f287c root: theorem check

      Three-term recurrence criterion [Sze39, §3.3; Fav35] polytool ?

    • preserver_image reversal, shift 0 e-1f661e973532853d

      Affine, reversal and Möbius substitutions (elementary) polytool ?

      • premise (sequence): Triangle read by rows: T(n,k) are the coefficients of Charlier polynomials: A046716 transposed, for 0 <= k <= n.
        uses: Every row P_n, n >= 1, is zero or real-rooted with all roots in (-inf, 0]
        • theorem_check three_term_recurrence e-503a12a637bb094e root: theorem check

          Three-term recurrence criterion [Sze39, §3.3; Fav35] polytool ?

        • preserver_image reversal, shift 0 e-10ee31afdeccb0f4

          Affine, reversal and Möbius substitutions (elementary) polytool ?

          • premise (sequence): Coefficients of a special case of Poisson-Charlier polynomials.
            uses: Every row P_n, n >= 1, is zero or real-rooted with all roots in (-inf, 0]
            • ↵ theorem_check three_term_recurrence e-3fcbce34648f287c (expanded above)

Related sequences ?

No candidate equalities or related sequences.

References

1. [Fav35] Jean Favard. Sur les polynômes de tchebicheff. C. R. Acad. Sci. Paris, 200:2052–2053, 1935.
2. [Sze39] G. Szegő. Orthogonal Polynomials. Colloquium publications, American Mathematical Society, 1939. doi:10.1090/coll/023