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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.

A145844 Number of permutations of length 2n which are invariant under the reverse-complement map and have no decreasing subsequences of length 5.

Table of values

n a(n)
0 1
1 2
2 8
3 46
4 332
5 2784
6 25888
7 259382
8 2749244
9 30449416
10 349379648
11 4127103776
12 49954287424
13 617299996928
14 7765434294912
15 99214734136966
16 1285011754097372
17 16845342401817048
18 223216584359771296
19 2986529546579794040
20 40308007404730514096
21 548337251596355725312

List of values

[1, 2, 8, 46, 332, 2784, 25888, 259382, 2749244, 30449416, 349379648, 4127103776, 49954287424, 617299996928, 7765434294912, 99214734136966, 1285011754097372, 16845342401817048, 223216584359771296, 2986529546579794040, 40308007404730514096, 548337251596355725312]

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

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