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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.

A000239 One-half of number of permutations of [n] with exactly one run of adjacent symbols differing by 1.

Table of values

n a(n)
1 1
2 1
3 3
4 8
5 28
6 143
7 933
8 7150
9 62310
10 607445
11 6545935
12 77232740
13 989893248
14 13692587323
15 203271723033
16 3223180454138
17 54362625941818
18 971708196867905
19 18347779304380995
20 364911199401630640
21 7624625589633857940
22 166977535317365068775
23 3824547112283439914893
24 91440772473772839055238

List of values

[1, 1, 3, 8, 28, 143, 933, 7150, 62310, 607445, 6545935, 77232740, 989893248, 13692587323, 203271723033, 3223180454138, 54362625941818, 971708196867905, 18347779304380995, 364911199401630640, 7624625589633857940, 166977535317365068775, 3824547112283439914893, 91440772473772839055238]

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

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