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.

A090628 Square array T(n,k) (row n, column k) read by antidiagonals defined by: T(n,k) is the permanent of the n X n matrix with 1 on the diagonal and k elsewhere; T(0,k)=1.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 5, 6, 1, 1, 1, 10, 29, 24, 1, 1, 1, 17, 82, 233, 120, 1, 1, 1, 26, 177, 1000, 2329, 720, 1, 1, 1, 37, 326, 2913, 14968, 27949, 5040, 1, 1, 1, 50, 541, 6776, 58017, 269488, 391285, 40320, 1, 1, 1, 65, 834, 13609, 168376, 1393137, 5659120, 6260561, 362880, 1
Offset: 0

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Author

Philippe Deléham, Dec 13 2003

Keywords

Examples

			Row n=0: 1,  1,   1,    1,    1,    1,     1,     1, ...
Row n=1: 1,  1,   1,    1,    1,    1,     1,     1, ...
Row n=2: 1,  2,   5,   10,   17,   26,    37,    50, ...
Row n=3: 1,  6,  29,   82,  177,  326,   541,   834, ...
Row n=4: 1, 24, 233, 1000, 2913, 6776, 13609, 24648, ...
		

Crossrefs

Cf. A008290.
Columns: A000012, A000142, A000354.

Programs

  • Maple
    T:= (n, k)-> `if`(n=0, 1, LinearAlgebra[Permanent](
                  Matrix(n, (i, j)-> `if`(i=j, 1, k)))):
    seq(seq(T(n, d-n), n=0..d), d=0..10);  # Alois P. Heinz, Jul 09 2017
    # second Maple program:
    b:= proc(n, k) b(n, k):= `if`(k=0, `if`(n<2, 1-n, (n-1)*
          (b(n-1, 0)+b(n-2, 0))), binomial(n, k)*b(n-k, 0))
        end:
    T:= proc(n, k) T(n, k):= add(b(n, j)*k^(n-j), j=0..n) end:
    seq(seq(T(n, d-n), n=0..d), d=0..10);  # Alois P. Heinz, Jul 09 2017
  • Mathematica
    T[0, _] = 1;
    T[n_, k_] := Permanent[Table[If[i == j, 1, k], {i, n}, {j, n}]];
    Table[T[n-k, k], {n, 0, 10}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Dec 07 2019 *)
  • PARI
    T(n,k) = matpermanent(matrix(n, n, i, j, if (i==j, 1, k)));
    matrix(10, 10, n, k, T(n,k)) \\ Michel Marcus, Dec 07 2019

Formula

T(n, k) = Sum_{j=0..n} A008290(n, j)*k^(n-j).

Extensions

3 terms corrected and more terms from Alois P. Heinz, Jul 09 2017