cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A193735 Mirror of the triangle A193734.

Original entry on oeis.org

1, 2, 1, 8, 6, 1, 32, 32, 10, 1, 128, 160, 72, 14, 1, 512, 768, 448, 128, 18, 1, 2048, 3584, 2560, 960, 200, 22, 1, 8192, 16384, 13824, 6400, 1760, 288, 26, 1, 32768, 73728, 71680, 39424, 13440, 2912, 392, 30, 1, 131072, 327680, 360448, 229376, 93184, 25088, 4480, 512, 34, 1
Offset: 0

Views

Author

Clark Kimberling, Aug 04 2011

Keywords

Comments

A193735 is obtained by reversing the rows of the triangle A193734.
Triangle T(n,k), read by rows, given by (2,2,0,0,0,0,0,0,0,...) DELTA (1,0,0,0,0,0,0,0,...) where DELTA is the operator defined in A084938. - Philippe Deléham, Oct 05 2011

Examples

			First six rows:
    1;
    2,   1;
    8,   6,   1;
   32,  32,  10,   1;
  128, 160,  72,  14,  1;
  512, 768, 448, 128, 18, 1;
		

Crossrefs

Programs

  • Magma
    function T(n, k) // T = A193735
      if k lt 0 or k gt n then return 0;
      elif n lt 2 then return n-k+1;
      else return 4*T(n-1, k) + T(n-1, k-1);
      end if;
    end function;
    [T(n, k): k in [0..n], n in [0..12]]; // G. C. Greubel, Nov 19 2023
    
  • Mathematica
    (* First program *)
    z = 8; a = 2; b = 1; c = 1; d = 2;
    p[n_, x_] := (a*x + b)^n ; q[n_, x_] := (c*x + d)^n
    t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0;
    w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1
    g[n_] := CoefficientList[w[n, x], {x}]
    TableForm[Table[Reverse[g[n]], {n, -1, z}]]
    Flatten[Table[Reverse[g[n]], {n, -1, z}]] (* A193734 *)
    TableForm[Table[g[n], {n, -1, z}]]
    Flatten[Table[g[n], {n, -1, z}]]      (* A193735 *)
    (* Second program *)
    T[n_, k_]:= T[n, k]= If[k<0 || k>n, 0, If[n<2, n-k+1, 4*T[n-1, k] + T[n -1, k-1]]];
    Table[T[n,k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Nov 19 2023 *)
  • SageMath
    def T(n, k): # T = A193735
        if (k<0 or k>n): return 0
        elif (n<2): return n-k+1
        else: return 4*T(n-1, k) + T(n-1, k-1)
    flatten([[T(n, k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Nov 19 2023

Formula

T(n,k) = A193734(n,n-k).
T(n,k) = T(n-1,k-1) + 4*T(n-1,k) with T(0,0)=T(1,1)=1 and T(1,0)=2. - Philippe Deléham, Oct 05 2011
G.f.: (1-2*x)/(1-4*x-x*y). - R. J. Mathar, Aug 11 2015
From G. C. Greubel, Nov 19 2023: (Start)
T(n, 0) = A081294(n).
Sum_{k=0..n} T(n, k) = A005053(n).
Sum_{k=0..n} (-1)^k * T(n, k) = A133494(n).
Sum_{k=0..floor(n/2)} T(n-k, k) = A001077(n).
Sum_{k=0..floor(n/2)} (-1)^k * T(n-k, k) = A001075(n). (End)