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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.

A306675 Number of permutations p of [2n] having at least one index i with |p(i)-i| = n.

Table of values

n a(n)
0 0
1 1
2 15
3 455
4 25487
5 2293839
6 302786759
7 55107190151
8 13225725636255
9 4047072044694047
10 1537887376983737879
11 710503968166486900119
12 392198190427900768865711
13 254928823778135499762712175
14 192726190776270437820610404327
15 167671785975355280903931051764519

List of values

[0, 1, 15, 455, 25487, 2293839, 302786759, 55107190151, 13225725636255, 4047072044694047, 1537887376983737879, 710503968166486900119, 392198190427900768865711, 254928823778135499762712175, 192726190776270437820610404327, 167671785975355280903931051764519]

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

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