A130534 → Pₙ + Pₙ₊₁

OEIS matches ?

• A001048: row sums, 15 terms agree OEIS nonn (row-sum match: finite agreement only) · view at the OEIS
• A261766: row sums, 15 terms agree OEIS nonn (row-sum match: finite agreement only) · view at the OEIS
• A059171: row sums, 15 terms agree OEIS nonn (row-sum match: finite agreement only) · view at the OEIS

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:       2,        1;
  1:       3,        4,        1;
  2:       8,       14,        7,       1;
  3:      30,       61,       41,      11,       1;
  4:     144,      324,      260,      95,      16,      1;
  5:     840,     2038,     1849,     820,     190,     22,      1;
  6:    5760,    14832,    14756,    7504,    2135,    343,     29,     1;
  7:   45360,   122652,   131256,   74053,   24409,   4858,    574,    37,    1;
  8:  403200,  1136160,  1290824,  790964,  291774,  67809,   9996,   906,   46,  1;
  9: 3991680, 11655216, 13926276, 9133180, 3686255, 965328, 167223, 19020, 1365, 56, 1;

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

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

P(N) = {my(v = vector(N + 1)); v[1] = 2 + x; for(n = 1, N, my(i = n + 1); v[i] = ((n^2 + 2*n + (2*n + 2)*x + x^2)*v[i - 1])/(n + 1 + x)); 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, +inf)
  Every polynomial of the sequence has only real roots, inside the stated interval.
  by the cited steps: e-d13f851235c1b0bb

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

• obreschkoff_combination e-d13f851235c1b0bb

  Hermite–Kakeya–Obreschkoff theorem [Obr63; Fis06, Thm 1.43] ?

  • premise (sequence): Triangle T(n,k), 0 <= k <= n, read by rows, giving coefficients of the polynomial (x+1)(x+2)...(x+n), expanded in incre…
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, +inf)
    • theorem_check liu_wang e-5f21311bb67f8c1c root: theorem check

      Liu–Wang theorem [LW07, Thm 2.1, Cor 2.4] ?

    • basis_map A007318 e-0b3ba9047fae59ed

      Geometric basis map (elementary) polytool ?

      • premise (sequence): Triangle of unsigned Stirling numbers of the first kind (see A048994), read by rows, T(n,k) for 0 <= k <= n.
        uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
        • parent_provers root_domain e-edbf92ee2e446027 root: theorem check

          Parent-row provers of polytool polytool ?

    • parent_provers root_domain e-2e5c10abc86c264d root: theorem check

      Parent-row provers of polytool polytool ?

    • preserver_image reversal, shift 0 e-90e69a839bdbf74b

      Affine, reversal and Möbius substitutions (elementary) polytool ?

      • premise (sequence): Triangle read by rows: T(n,k) = |s(n,n+1-k)|, where s(n,k) are the signed Stirling numbers of the first kind A008276 (1…
        uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
        • theorem_check liu_wang e-419a6747cb084155 root: theorem check

          Liu–Wang theorem [LW07, Thm 2.1, Cor 2.4] ?

        • preserver_image reversal, shift 0 e-986a227a8a459030

          Affine, reversal and Möbius substitutions (elementary) polytool ?

          • premise (sequence): Triangle T(n,k), 0 <= k <= n, read by rows, giving coefficients of the polynomial (x+1)(x+2)...(x+n), expanded in incre…
            uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
            • ↵ theorem_check liu_wang e-5f21311bb67f8c1c (expanded above)
            • ↵ basis_map A007318 e-0b3ba9047fae59ed (expanded above)
            • ↵ parent_provers root_domain e-2e5c10abc86c264d (expanded above)
            • preserver_image affine, shift 0 e-1ba7a8eebd893648

              Affine, reversal and Möbius substitutions (elementary) polytool ?

              • premise (sequence): Triangle of unsigned Stirling numbers of the first kind (see A048994), read by rows, T(n,k) for 0 <= k <= n.
                uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
                • ↵ parent_provers root_domain e-edbf92ee2e446027 (expanded above)
        • parent_provers paper_theorem e-b29f35705824bef6 root: theorem check

          Parent-row provers of polytool polytool ?

    • ↵ preserver_image affine, shift 0 e-1ba7a8eebd893648 (expanded above)
  • premise (sequence): Triangle T(n,k), 0 <= k <= n, read by rows, giving coefficients of the polynomial (x+1)(x+2)...(x+n), expanded in incre…
    uses: Rows P_(m-1), P_m interlace (weak, unordered) for every m >= 1
    no recorded property covers this requirement

Related sequences ?

No candidate equalities or related sequences.

References

1. [Fis06] Steve Fisk. Polynomials, roots, and interlacing. arXiv:math/0612833. arXiv
2. [LW07] Lily L. Liu and Yi Wang. A unified approach to polynomial sequences with only real zeros. Advances in Applied Mathematics, 38(4):542–560, May 2007. doi:10.1016/j.aam.2006.02.003
3. [Obr63] Nikola Obreschkoff. Verteilung und berechnung der nullstellen reeller polynome. Hochschulbücher für mathematik, VEB Deutscher Verlag der Wissenschaften, 1963.