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.

A209769 Triangle of coefficients of polynomials u(n,x) jointly generated with A209770; see the Formula section.

Original entry on oeis.org

1, 1, 2, 3, 5, 3, 5, 12, 11, 5, 9, 26, 34, 24, 8, 15, 53, 88, 86, 48, 13, 25, 104, 210, 258, 200, 93, 21, 41, 198, 470, 695, 680, 440, 175, 34, 67, 369, 1007, 1737, 2043, 1671, 929, 323, 55, 109, 676, 2085, 4107, 5625, 5529, 3895, 1901, 587, 89, 177
Offset: 1

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Author

Clark Kimberling, Mar 15 2012

Keywords

Comments

Column 1: A001595
Row n ends with F(n+1), where F=A000045 (Fibonacci numbers).
Row sums: 1,3,11,33,101,303,911,2733,... A081250
Alternating row sums: 1,-1,1,-1,1,-1,... A033999
For a discussion and guide to related arrays, see A208510.

Examples

			First five rows:
1
1...2
3...5....3
5...12...11...5
9...26...34...24...8
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_] := (x + 1)*u[n - 1, x] + 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[%]    (* A209769 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A209770 *)

Formula

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