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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.

A229244 Number of n-permutations such that at least one cycle has size ceiling(n/2).

Table of values

n a(n)
1 1
2 1
3 3
4 9
5 40
6 200
7 1260
8 8820
9 72576
10 653184
11 6652800
12 73180800
13 889574400
14 11564467200
15 163459296000
16 2451889440000
17 39520825344000
18 671854030848000
19 12164510040883200
20 231125690776780800
21 4644631106519040000
22 97537253236899840000
23 2154334728240414720000
24 49549698749529538560000
25 1193170003333152768000000

List of values

[1, 1, 3, 9, 40, 200, 1260, 8820, 72576, 653184, 6652800, 73180800, 889574400, 11564467200, 163459296000, 2451889440000, 39520825344000, 671854030848000, 12164510040883200, 231125690776780800, 4644631106519040000, 97537253236899840000, 2154334728240414720000, 49549698749529538560000, 1193170003333152768000000]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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