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.

A006213 Number of down-up permutations of n+4 starting with n+1.

Table of values

n a(n)
0 0
1 2
2 10
3 46
4 224
5 1202
6 7120
7 46366
8 329984
9 2551202
10 21306880
11 191252686
12 1836652544
13 18793429202
14 204154071040
15 2346705139006
16 28459289083904
17 363156549211202
18 4864231397785600
19 68237760828425326
20 1000569392347480064
21 15306487540377673202

List of values

[0, 2, 10, 46, 224, 1202, 7120, 46366, 329984, 2551202, 21306880, 191252686, 1836652544, 18793429202, 204154071040, 2346705139006, 28459289083904, 363156549211202, 4864231397785600, 68237760828425326, 1000569392347480064, 15306487540377673202]

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

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