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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.

A321315 Number of permutations of [n] where the length of the longest increasing subsequence is larger than or equal to the length of the longest decreasing subsequence.

Table of values

n a(n)
1 1
2 1
3 5
4 14
5 78
6 488
7 3161
8 25092
9 231428
10 2299664
11 24809824
12 296046900
13 3863542365
14 54081895706
15 806425921874
16 12828011279528
17 217574673205512
18 3914918953508792
19 74300528009315864
20 1482219340166034896
21 31035891175182089248
22 681299189806864371412
23 15649118660372502746968

List of values

[1, 1, 5, 14, 78, 488, 3161, 25092, 231428, 2299664, 24809824, 296046900, 3863542365, 54081895706, 806425921874, 12828011279528, 217574673205512, 3914918953508792, 74300528009315864, 1482219340166034896, 31035891175182089248, 681299189806864371412, 15649118660372502746968]

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

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