A135838 → x ↦ x/(x+1)

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;
  1:  2,   4;
  2:  2,   8,    8;
  3:  4,  24,   48,    32;
  4:  4,  32,   96,   128,    64;
  5:  8,  80,  320,   640,   640,    256;
  6:  8,  96,  480,  1280,  1920,   1536,    512;
  7: 16, 224, 1344,  4480,  8960,  10752,   7168,   2048;
  8: 16, 256, 1792,  7168, 17920,  28672,  28672,  16384,  4096;
  9: 32, 576, 4608, 21504, 64512, 129024, 172032, 147456, 73728, 16384;

The row polynomials satisfy (1+2*x+x^2)*P(n,x) = (2+12*x+26*x^2+24*x^3+8*x^4)*P(n-2,x) for n >= 2, with P(0,x) = 1, P(1,x) = 2 + 4*x.

P[0, x_] := 1;
P[1, x_] := 2 + 4*x;
P[n_, x_] := P[n, x] = Expand[Together[((2 + 12*x + 26*x^2 + 24*x^3 + 8*x^4)*P[n - 2, x])/(1 + 2*x + x^2)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten

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] = ((2 + 12*x + 26*x^2 + 24*x^3 + 8*x^4)*v[i - 2])/(1 + 2*x + x^2)); 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 [-1, 0]
  Every polynomial of the sequence has only real roots, inside the stated interval.
  by the cited steps: e-9f3b1e4aefe8044e
• 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-9f3b1e4aefe8044e
• 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-9f3b1e4aefe8044e

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

• preserver_image mobius, shift 0 e-9f3b1e4aefe8044e

  Affine, reversal and Möbius substitutions (elementary) polytool ?

  • premise (sequence): Triangle read by rows: T(n,k) = 2^floor(n/2)*binomial(n-1,k-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-07f7d31230240b98

      Affine, reversal and Möbius substitutions (elementary) polytool ?

      • premise (sequence): Triangle read by rows: T(n,k) = 2^floor(n/2)*binomial(n-1,k-1).
        uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
        • parent_provers periodic_product e-51cb02553cf4a8ac root: theorem check

          Parent-row provers of polytool polytool ?

    • ↵ parent_provers periodic_product e-51cb02553cf4a8ac (expanded above)

Related sequences ?

Same fingerprint (67)

Equal up to content, sign, reversal and a small index shift.

• A120909: Triangle read by rows: T(n,k) is the number of ternary words of length n having k runs (i.e., subwords of maxi…
• A178820 → x ↦ x/(x+1)
• A038208 → basis A007318
• A038325 → basis A007318
• basis-map coefficients of A113214, shifted → basis A013611
• A120910 → D
• A344565 → x ↦ x/(x+1)
• A007318 → ×(1+(3/2)n+(1/2)n²) → x ↦ x+1
• basis-map coefficients of A113214, shifted → x ↦ x+1
• A085880 → x ↦ x/(x+1)
• A013609 → basis A013610
• A178820 → basis A007318
• A027466 → basis A013611
• A013609 → D
• A344565 → basis A013611
• A135838 → basis A013611
• A038208 → basis A013611
• A085881 → basis A007318
• A196347 → basis A007318
• A038330 → basis A013609
• A130123 → basis A013609
• A356546 → basis A007318
• A159854 → x ↦ x/(x+1)
• A038207: Triangle whose (i,j)-th entry is binomial(i,j)*2^(i-j).
• A135838 → x ↦ x+1
• basis-map coefficients of A113214, shifted → x ↦ x/(x+1)
• A028326 → basis A013611
• A344565 → basis A007318
• A178820 → basis A013611
• A156992 → basis A013611
• A007318 → D → x ↦ x/(x+1)
• A007318 → ×(1+2n+n²) → x ↦ x+1
• A038208 → x ↦ x/(x+1)
• A178821 → x ↦ x/(x+1)
• A178821 → basis A013611
• A007318 → ×(1+(3/2)n+(1/2)n²) → x ↦ x/(x+1)
• A178821 → basis A007318
• A007318 → ×(−(1/2)n+(1/2)n²) → x ↦ x/(x+1)
• A178822 → basis A013611
• A038338 → basis A013611
• basis-map coefficients of A026729 → basis A013609
• A085881 → basis A013611
• A136572 → basis A013609
• A007318 → ×(1+2n+n²) → x ↦ x/(x+1)
• basis-map coefficients of A112227 → basis A013609
• A007318 → ×(−(1/2)n+(1/2)n²) → x ↦ x+1
• basis-map coefficients of A030528, shifted → basis A013609
• A085880 → basis A013611
• A038243 → basis A013610
• A038325 → basis A013611
• A038207 → D
• A028326 → basis A007318
• A085880 → x ↦ x+1
• A120910: Triangle read by rows: T(n,k) is the number of ternary words of length n having k levels (n >= 1, 0 <= k <= n-…
• A196347 → basis A013611
• A038221 → basis A013611
• A178822 → x ↦ x+1
• basis-map coefficients of A021012 → basis A013609
• A356546 → basis A013611
• A120909 → basis A013610
• A120909 → D
• basis-map coefficients of A026729, shifted → basis A013609
• A013609: Triangle of coefficients in expansion of (1+2*x)^n.
• A156992 → basis A007318
• A038338 → basis A007318
• A028326 → x ↦ x/(x+1)
• A178822 → x ↦ x/(x+1)