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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.

A145847 Number of involutions of length 2n which are invariant under the reverse-complement map and have no decreasing subsequences of length 6.

Table of values

n a(n)
0 1
1 2
2 6
3 19
4 67
5 246
6 947
7 3746
8 15213
9 62950
10 264920
11 1129965
12 4877215
13 21262918
14 93522756
15 414532163
16 1850047621
17 8307290058
18 37507875950
19 170191051327
20 775719275151
21 3550191976022
22 16309030657001
23 75179696666964
24 347658070586857
25 1612424809368446

List of values

[1, 2, 6, 19, 67, 246, 947, 3746, 15213, 62950, 264920, 1129965, 4877215, 21262918, 93522756, 414532163, 1850047621, 8307290058, 37507875950, 170191051327, 775719275151, 3550191976022, 16309030657001, 75179696666964, 347658070586857, 1612424809368446]

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

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