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.

A193909 Mirror of the triangle A193908.

Original entry on oeis.org

1, 1, 2, 3, 6, 8, 6, 12, 20, 24, 11, 22, 40, 64, 80, 19, 38, 72, 128, 208, 256, 32, 64, 124, 232, 416, 672, 832, 53, 106, 208, 400, 752, 1344, 2176, 2688, 87, 174, 344, 672, 1296, 2432, 4352, 7040, 8704, 142, 284, 564, 1112, 2176, 4192, 7872, 14080, 22784
Offset: 0

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Author

Clark Kimberling, Aug 09 2011

Keywords

Comments

A193909 is obtained by reversing the rows of the triangle A193908.

Examples

			First six rows:
1
1....2
3....6....8
6....12...20...24
11...22...40...64....80
19...38...72...128...208...256
		

Crossrefs

Cf. A193908.

Programs

  • Mathematica
    z = 12;
    p[n_, x_] := Sum[Fibonacci[k + 2]*x^(n - k), {k, 0, n}];
    q[n_, x_] := 2 x*q[n - 1, x] + 1 ; q[0, x_] := 1;
    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}]]  (* A193908 *)
    TableForm[Table[g[n], {n, -1, z}]]
    Flatten[Table[g[n], {n, -1, z}]]  (* A193909 *)

Formula

Write w(n,k) for the triangle at A193908. The triangle at A193909 is then given by w(n,n-k).