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.

A209753 Triangle of coefficients of polynomials u(n,x) jointly generated with A209754; see the Formula section.

Original entry on oeis.org

1, 1, 2, 3, 5, 3, 5, 14, 12, 4, 9, 30, 40, 23, 5, 15, 63, 107, 93, 39, 6, 25, 124, 264, 300, 190, 61, 7, 41, 238, 604, 858, 722, 354, 90, 8, 67, 445, 1319, 2242, 2364, 1559, 615, 127, 9, 109, 818, 2772, 5500, 6966, 5783, 3101, 1011, 173, 10, 177, 1482
Offset: 1

Views

Author

Clark Kimberling, Mar 14 2012

Keywords

Comments

Alternating row sums: 1,-1,1,-1,1,-1,1,-1,...
For a discussion and guide to related arrays, see A208510.

Examples

			First five rows:
1
1...2
3...5....3
5...14...12...4
9...30...40...23...5
First three polynomials u(n,x): 1, 1 + 2x, 3 + 5x + 3x^2.
		

Crossrefs

Programs

  • Mathematica
    u[1, x_] := 1; v[1, x_] := 1; z = 16;
    u[n_, x_] := x*u[n - 1, x] + (x + 1)*v[n - 1, x];
    v[n_, x_] := u[n - 1, x] + (x + 1)*v[n - 1, x] + 1;
    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[%]    (* A209753 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A209754 *)

Formula

u(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x),
v(n,x)=u(n-1,x)+(x+1)*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.