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.

A330490 Total number of permutation arrays of side length n and dimension k as defined by Eriksson and Linusson (2000a); square array T(n,k), read by ascending antidiagonals, for n, k >= 1.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 6, 5, 1, 1, 24, 70, 15, 1, 1, 120, 2167, 1574, 52, 1, 1, 720, 130708, 968162, 69874, 203, 1, 1, 5040, 14231289
Offset: 1

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Author

Petros Hadjicostas, Dec 16 2019

Keywords

Comments

The poset P_{3 x 3} of (3 x 3 x 3)-permutation arrays is shown in Figure 1 on p. 209 of Eriksson and Linuson (2000a). We have |P_{3 x 3}| = T(3,3) = 70. The numbers in this rectangular array are copied from Table 1 (p. 210) of the same paper.

Examples

			Array T(n,k) (with rows n >= 1 and columns k >= 1) begins as follows, where * indicates a missing number:
  1,     1,            1,      1,     1, ...
  1,     2,            5,     15,    52, ...
  1,     6,           70,   1574, 69874, ...
  1,    24,         2167, 968162,     *, ...
  1,   120,       130708,      *,     *, ...
  1,   720,     14231289,      *,     *, ...
  1,  5040,   2664334184,      *,     *, ...
  1, 40320, 831478035698,      *,     *, ...
  ...
		

Crossrefs

Formula

T(n=1,k) = 1 = A000012(n) and T(n=2,k) = A000110(k) (Bell numbers).
T(n,k=1) = 1 = A000012(n) and T(n,k=2) = n! = A000142(n).
T(n,k) >= (n!)^(k-1) = A225816(k-1, n).
T(n,k=3) <= n!*2^(binomial(n+1,2) - 1).