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.

A258667 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 9 seats clockwise from his wife's chair.

Table of values

n a(n)
1 0
2 0
3 0
4 0
5 0
6 20
7 116
8 791
9 6205
10 55004
11 543596
12 5922929
13 70518903
14 910711188
15 12678337924
16 189252400363
17 3015217931281
18 51067619058668
19 916176426367084
20 17355904144230373
21 346195850528456683
22 7252654441430368404
23 159210363452786908116
24 3654550890657000160319

List of values

[0, 0, 0, 0, 0, 20, 116, 791, 6205, 55004, 543596, 5922929, 70518903, 910711188, 12678337924, 189252400363, 3015217931281, 51067619058668, 916176426367084, 17355904144230373, 346195850528456683, 7252654441430368404, 159210363452786908116, 3654550890657000160319]

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

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