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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.

A358112 Table read by rows. A statistic of permutations of the multiset {1,1,2,2,...,n,n}.

Original entry on oeis.org

1, 5, 1, 47, 42, 1, 641, 1659, 219, 1, 11389, 72572, 28470, 968, 1, 248749, 3610485, 3263402, 357746, 4017, 1, 6439075, 204023334, 371188155, 95559940, 3853617, 16278, 1, 192621953, 12989570167, 43844432805, 22448025251, 2216662051, 38270373, 65399, 1
Offset: 1

Views

Author

Peter Luschny, Oct 30 2022

Keywords

Comments

Table 1, page 12 in Maazouz and Pitman (note a typo in T(2, 0)).

Examples

			[n\d]    0            1           2           3           4           5     6
-----------------------------------------------------------------------------
[1]         1;
[2]         5,           1;
[3]        47,          42,           1;
[4]       641,        1659,         219,           1;
[5]     11389,       72572,       28470,         968,          1;
[6]    248749,     3610485,     3263402,      357746,       4017,        1;
[7]   6439075,   204023334,   371188155,    95559940,    3853617,    16278, 1
[8] 192621953, 12989570167, 43844432805, 22448025251, 2216662051, 38270373,
65399, 1
		

Crossrefs

Cf. A006902 (row 0), A000680 (row sums).

Programs

  • Maple
    P := (n, x) -> (2*n)!*add(add(binomial(n, k)*binomial(n-k, j)*
    (-1)^(n-k-j)*max(x - k, 0)^(2*n - j)/(2*n - j)!, j = 0..n-k), k = 0..n):
    Trow := n -> seq(P(n, k+1) - P(n, k), k = 0..n-1):
    seq(print(Trow(n)), n = 1..8);

Formula

T(n, k) = P(n, k+1) - P(n, k), where P(n, x) = (2*n)!*Sum_{k=0..n} Sum_{j=0..n-k} binomial(n, k)*binomial(n-k, j)*(-1)^(n-k-j)*max(x - k, 0)^(2*n - j)/(2*n - j)!.