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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.

A145870 Number of involutions of length 2n which are invariant under the reverse-complement map and have no decreasing subsequences of length 8.

Table of values

n a(n)
0 1
1 2
2 6
3 20
4 75
5 301
6 1287
7 5762
8 26875
9 129520
10 642452
11 3264834
12 16950089
13 89646090
14 482012650
15 2629809994
16 14537429823
17 81313943942
18 459705628930
19 2624247237560
20 15113949789357
21 87755911422989
22 513357330465591
23 3023830805847910
24 17925386942479025

List of values

[1, 2, 6, 20, 75, 301, 1287, 5762, 26875, 129520, 642452, 3264834, 16950089, 89646090, 482012650, 2629809994, 14537429823, 81313943942, 459705628930, 2624247237560, 15113949789357, 87755911422989, 513357330465591, 3023830805847910, 17925386942479025]

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

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