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.

A209134 Triangle of coefficients of polynomials v(n,x) jointly generated with A209133; see the Formula section.

Original entry on oeis.org

1, 0, 4, 0, 4, 10, 0, 4, 18, 28, 0, 4, 26, 72, 76, 0, 4, 34, 132, 256, 208, 0, 4, 42, 208, 572, 864, 568, 0, 4, 50, 300, 1056, 2272, 2808, 1552, 0, 4, 58, 408, 1740, 4800, 8496, 8896, 4240, 0, 4, 66, 532, 2656, 8880, 20208, 30432, 27648, 11584, 0, 4, 74
Offset: 1

Views

Author

Clark Kimberling, Mar 05 2012

Keywords

Comments

For a discussion and guide to related arrays, see A208510.
As triangle T(n,k) with 0<=k<=n, it is (0, 1, 0, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (4, -3/2, -1/2, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Apr 10 2012

Examples

			First five rows:
1
0...4
0...4...10
0...4...18...28
0...4...26...72...76
First three polynomials v(n,x): 1, 4x, 4x + 10x^2.
		

Crossrefs

Programs

  • Mathematica
    u[1, x_] := 1; v[1, x_] := 1; z = 16;
    u[n_, x_] := u[n - 1, x] + (x + 1)*v[n - 1, x];
    v[n_, x_] := 2 x*u[n - 1, x] + 2 x*v[n - 1, x];
    Table[Expand[u[n, x]], {n, 1, z/2}]
    Table[Expand[v[n, x]], {n, 1, z/2}]
    cu = Table[CoefficientList[u[n, x], x], {n, 1, z}];
    TableForm[cu]
    Flatten[%]    (* A209133 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A209134 *)

Formula

u(n,x)=u(n-1,x)+(x+1)*v(n-1,x),
v(n,x)=2x*u(n-1,x)+2x*v(n-1,x),
where u(1,x)=1, v(1,x)=1.
T(n,k) = T(n-1,k) + 2*T(n-1,k-1) + 2*T(n-2,k-2), T(1,0) = 1, T(2,0) = 0, T(2,1) = 4 and T(n,k) = 0 if k<0 or if k>=n. - Philippe Deléham, Apr 10 2012