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.

A006216 Number of down-up permutations of n+4 starting with 4.

Table of values

n a(n)
0 2
1 5
2 14
3 46
4 178
5 800
6 4094
7 23536
8 150178
9 1053440
10 8057774
11 66750976
12 595380178
13 5688903680
14 57975175454
15 627692271616
16 7195247514178
17 87056789995520
18 1108708685037134
19 14825405274259456
20 207676251991176178

List of values

[2, 5, 14, 46, 178, 800, 4094, 23536, 150178, 1053440, 8057774, 66750976, 595380178, 5688903680, 57975175454, 627692271616, 7195247514178, 87056789995520, 1108708685037134, 14825405274259456, 207676251991176178]

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

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