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.

A002467 The game of Mousetrap with n cards (given n letters and n envelopes, how many ways are there to fill the envelopes so that at least one letter goes into its right envelope?).

Table of values

n a(n)
0 0
1 1
2 1
3 4
4 15
5 76
6 455
7 3186
8 25487
9 229384
10 2293839
11 25232230
12 302786759
13 3936227868
14 55107190151
15 826607852266
16 13225725636255
17 224837335816336
18 4047072044694047
19 76894368849186894
20 1537887376983737879
21 32295634916658495460
22 710503968166486900119

List of values

[0, 1, 1, 4, 15, 76, 455, 3186, 25487, 229384, 2293839, 25232230, 302786759, 3936227868, 55107190151, 826607852266, 13225725636255, 224837335816336, 4047072044694047, 76894368849186894, 1537887376983737879, 32295634916658495460, 710503968166486900119]

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

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