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.

A193094 Augmentation of the triangular array P=A130296 whose n-th row is (n+1,1,1,1,1...,1) for 0<=k<=n. See Comments.

Original entry on oeis.org

1, 2, 1, 6, 4, 3, 24, 18, 16, 13, 120, 96, 90, 84, 71, 720, 600, 576, 558, 532, 461, 5040, 4320, 4200, 4128, 4050, 3908, 3447, 40320, 35280, 34560, 34200, 33888, 33462, 32540, 29093, 362880, 322560, 317520, 315360, 313800, 312096, 309330, 302436
Offset: 0

Views

Author

Clark Kimberling, Jul 30 2011

Keywords

Comments

For an introduction to the unary operation "augmentation" as applied to triangular arrays or sequences of polynomials, see A193091.
Regarding W=A193093:
col 1: A000142, n!
col 2: A001593, n*n!
col 3: A130744, n*(n+2)*n!
diag (1,1,3,13,71,...): A003319, indecomposable permutations.
It appears that T(n,k) is the number of indecomposable permutations p of [n+2] for which p(k+2) = 1. For example, T(2,1) = 4 counts 2413, 3412, 4213, 4312. - David Callan, Aug 27 2014

Examples

			First 5 rows:
1
2.....1
6.....4....3
24....18...16...13
120...96...90...84...71
		

Crossrefs

Programs

  • Mathematica
    p[n_, k_] := If[k == 0, n + 1, 1]
    Table[p[n, k], {n, 0, 5}, {k, 0, n}] (* A130296 *)
    m[n_] := Table[If[i <= j, p[n + 1 - i, j - i], 0], {i, n}, {j, n + 1}]
    TableForm[m[4]]
    w[0, 0] = 1; w[1, 0] = p[1, 0]; w[1, 1] = p[1, 1];
    v[0] = w[0, 0]; v[1] = {w[1, 0], w[1, 1]};
    v[n_] := v[n - 1].m[n]
    TableForm[Table[v[n], {n, 0, 6}]] (* A193094 *)
    Flatten[Table[v[n], {n, 0, 9}]]