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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.

A145845 Number of permutations of length 2n+1 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 7
3 34
4 208
5 1504
6 12283
7 109778
8 1050820
9 10614856
10 111978128
11 1224261856
12 13792583296
13 159411938560
14 1883550536707
15 22687603653106
16 277940485660012
17 3456490397570392
18 43565433620294908
19 555752354850506312
20 7167182317486700416
21 93348781597357983232
22 1226830676118851157712

List of values

[1, 2, 7, 34, 208, 1504, 12283, 109778, 1050820, 10614856, 111978128, 1224261856, 13792583296, 159411938560, 1883550536707, 22687603653106, 277940485660012, 3456490397570392, 43565433620294908, 555752354850506312, 7167182317486700416, 93348781597357983232, 1226830676118851157712]

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

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