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.

A209756 Triangle of coefficients of polynomials v(n,x) jointly generated with A209755; see the Formula section.

Original entry on oeis.org

1, 2, 1, 3, 2, 2, 4, 4, 6, 3, 5, 7, 13, 11, 5, 6, 11, 24, 28, 22, 8, 7, 16, 40, 59, 63, 41, 13, 8, 22, 62, 110, 146, 132, 76, 21, 9, 29, 91, 188, 296, 337, 271, 138, 34, 10, 37, 128, 301, 546, 743, 754, 541, 248, 55, 11, 46, 174, 458, 938, 1477, 1793, 1632
Offset: 1

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Author

Clark Kimberling, Mar 14 2012

Keywords

Comments

Column 1: 1,2,3,4,5,6,....... A000027
Column 2: 1,2,4,7,11,........ A000124
Column 3: 2,6,13,24,......... A003600
Last term in row n: 1,1,2,3,. A000045 (Fibonacci numbers)
Row sums: 1,3,7,17,41,...... A001333
Alternating row sums: 1,2,3,3,5,5,7,7,...; A109613
For a discussion and guide to related arrays, see A208510.

Examples

			First five rows:
1
2...1
3...2...2
4...4...6....3
5...7...13...11...5
First three polynomials v(n,x): 1, 2 + x , 3 + 2x + 2x^2.
		

Crossrefs

Cf. A208510.

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*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[%]    (* A209755 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A209756 *)
    Table[u[n, x] /. x -> 1, {n, 1, z}]   (* A133654 *)
    Table[v[n, x] /. x -> 1, {n, 1, z}]   (* A001333 *)
    Table[u[n, x] /. x -> -1, {n, 1, z}]  (* A033999 *)
    Table[v[n, x] /. x -> -1, {n, 1, z}]  (* A109613 *)

Formula

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