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.

A193851 Mirror of the triangle A193850.

Original entry on oeis.org

2, 8, 4, 26, 20, 8, 80, 72, 48, 16, 242, 232, 192, 112, 32, 728, 716, 656, 496, 256, 64, 2186, 2172, 2088, 1808, 1248, 576, 128, 6560, 6544, 6432, 5984, 4864, 3072, 1280, 256, 19682, 19664, 19520, 18848, 16832, 12800, 7424, 2816, 512, 59048, 59028
Offset: 0

Views

Author

Clark Kimberling, Aug 07 2011

Keywords

Comments

A193851 is obtained by reversing the rows of the triangle A193850.

Examples

			First six rows:
2
8....4
26...20....8
80...72...40..16
242...232...192...112...32
728...716...656...496..256..64
		

Crossrefs

Programs

  • Mathematica
    z = 10;
    p[n_, x_] := (x + 2)^n;
    q[0, x_] := 1; q[n_, x_] := x*q[n - 1, x] + 1;
    p1[n_, k_] := Coefficient[p[n, x], x^k];
    p1[n_, 0] := p[n, x] /. x -> 0;
    d[n_, x_] := Sum[p1[n, k]*q[n - 1 - k, x], {k, 0, n - 1}]
    h[n_] := CoefficientList[d[n, x], {x}]
    TableForm[Table[Reverse[h[n]], {n, 0, z}]]
    Flatten[Table[Reverse[h[n]], {n, -1, z}]]  (* A193850 *)
    TableForm[Table[h[n], {n, 0, z}]]
    Flatten[Table[h[n], {n, -1, z}]]   (* A193851  *)
    TableForm[Table[Reverse[h[n]/2], {n, 0, z}]]
    Flatten[Table[Reverse[h[n]]/2, {n, -1, z}]] (* A193852 *)
    TableForm[Table[h[n]/2, {n, 0, z}]]
    Flatten[Table[h[n]/2, {n, -1, z}]]  (* A193853 *)

Formula

Write w(n,k) for the triangle at A193850. The triangle at A193851 is then given by w(n,n-k).