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.

A258665 A total of n married couples, including a mathematician M and his wife, are to be seated at the 2n chairs around a circular table, with no man seated next to his wife. After the ladies are seated at every other chair, M is the first man allowed to choose one of the remaining chairs. The sequence gives the number of ways of seating the other men, with no man seated next to his wife, if M chooses the chair that is 5 seats clockwise from his wife's chair.

Table of values

n a(n)
1 0
2 0
3 0
4 1
5 5
6 20
7 116
8 791
9 6203
10 55000
11 543576
12 5922813
13 70518113
14 910704988
15 12678282940
16 189251856883
17 3015212009143
18 51067548545968
19 916175515710896
20 17355891466436025
21 346195661281979133
22 7252651426282955236
23 159210312386078554436
24 3654549974493252076175

List of values

[0, 0, 0, 1, 5, 20, 116, 791, 6203, 55000, 543576, 5922813, 70518113, 910704988, 12678282940, 189251856883, 3015212009143, 51067548545968, 916175515710896, 17355891466436025, 346195661281979133, 7252651426282955236, 159210312386078554436, 3654549974493252076175]

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

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