A102547 → reverse → basis A013610

OEIS matches ?

No OEIS matches.

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:
  0:  1,   3;
  1:  1,   6,    9;
  2:  1,   9,   27,    27;
  3:  2,  21,   81,   135,     81;
  4:  3,  39,  198,   486,    567,    243;
  5:  4,  63,  405,  1350,   2430,   2187,    729;
  6:  6, 108,  819,  3375,   8100,  11178,   8019,   2187;
  7:  9, 183, 1602,  7857,  23490,  43497,  48114,  28431,   6561;
  8: 13, 297, 2970, 17010,  61236, 142884, 214326, 196830,  98415,  19683;
  9: 19, 480, 5382, 35181, 147987, 416745, 790965, 990711, 774198, 334611, 59049;

The row polynomials satisfy P(n,x) = (1+6*x+9*x^2)*P(n-3,x) + (1+3*x)*P(n-1,x) for n >= 3, with P(0,x) = 1 + 3*x, P(1,x) = 1 + 6*x + 9*x^2, P(2,x) = 1 + 9*x + 27*x^2 + 27*x^3.

P[0, x_] := 1 + 3*x;
P[1, x_] := 1 + 6*x + 9*x^2;
P[2, x_] := 1 + 9*x + 27*x^2 + 27*x^3;
P[n_, x_] := P[n, x] = Expand[(1 + 6*x + 9*x^2)*P[n - 3, x] + (1 + 3*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten

P(N) = {my(v = vector(N + 1)); v[1] = 1 + 3*x; v[2] = 1 + 6*x + 9*x^2; v[3] = 1 + 9*x + 27*x^2 + 27*x^3; for(n = 3, N, my(i = n + 1); v[i] = (1 + 6*x + 9*x^2)*v[i - 3] + (1 + 3*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)

Proved properties

• Real-rooted. Every row P_n, n >= 0, 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-714d743cdbf8af98
• Coefficients of one sign. Every nonzero row, n >= 0: 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-714d743cdbf8af98
• Hadamard kernel (Malo). Rows P_n, n >= 0, 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-714d743cdbf8af98

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 A013610 e-714d743cdbf8af98

  Geometric basis map (elementary) polytool ?

  • premise (sequence): Square array read by antidiagonals downwards: T(n,k), n>=0, k>=0, in which column 0 is equal to A057427: 0, 1, 1, 1, ..…
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
    • preserver_image reversal, shift 0 e-0e9e334768ea0a35

      Affine, reversal and Möbius substitutions (elementary) polytool ?

      • premise (sequence): Triangle read by rows, formed from antidiagonals of the antidiagonals (A011973) of Pascal's triangle (A007318).
        uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
        • preserver_image reversal, shift 0 e-9cfbf7a52f4ba322

          Affine, reversal and Möbius substitutions (elementary) polytool ?

          • premise (sequence): Square array read by antidiagonals downwards: T(n,k), n>=0, k>=0, in which column 0 is equal to A057427: 0, 1, 1, 1, ..…
            uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
            no recorded property covers this requirement
        • parent_provers paper_theorem e-eef18680cd27a7c9 root: theorem check

          Parent-row provers of polytool polytool ?

Related sequences ?

No candidate equalities or related sequences.