cp's OEIS Frontend

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.

A226439 Number of permutations of {1..n} with fewer than 6 interior elements having values lying between the values of their neighbors.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 24
5 120
6 720
7 5040
8 40318
9 362370
10 3600306
11 38963958
12 453658380
13 5626972260
14 73801171100
15 1017828597300
16 14699233982370
17 221584676368350
18 3477976352489742
19 56725919426072106
20 959792584260031648
21 16822545496476258000
22 305055135390508456872

List of values

[1, 1, 2, 6, 24, 120, 720, 5040, 40318, 362370, 3600306, 38963958, 453658380, 5626972260, 73801171100, 1017828597300, 14699233982370, 221584676368350, 3477976352489742, 56725919426072106, 959792584260031648, 16822545496476258000, 305055135390508456872]

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

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