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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.

A317281 Number of permutations of [n] with exactly one increasing run of even length.

Table of values

n a(n)
2 1
3 4
4 12
5 52
6 299
7 1750
8 11195
9 83074
10 675304
11 5880354
12 55691345
13 570430818
14 6235219145
15 72578854088
16 898625380692
17 11776375141808
18 162751388533495
19 2367374376626798
20 36156236738459671
21 578320016708416430
22 9668632218886209536
23 168657264917156460894

List of values

[1, 4, 12, 52, 299, 1750, 11195, 83074, 675304, 5880354, 55691345, 570430818, 6235219145, 72578854088, 898625380692, 11776375141808, 162751388533495, 2367374376626798, 36156236738459671, 578320016708416430, 9668632218886209536, 168657264917156460894]

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

Content is available under The OEIS End-User License Agreement.