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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.

A334680 a(n) is the total number of down-steps after the final up-step in all 2-Dyck paths of length 3*n (n up-steps and 2*n down-steps).

Table of values

n a(n)
0 0
1 2
2 9
3 43
4 218
5 1155
6 6324
7 35511
8 203412
9 1184040
10 6983925
11 41652468
12 250763464
13 1521935948
14 9301989144
15 57203999295
16 353701790376
17 2197600497330
18 13713291247635
19 85907187607395
20 540072341320050
21 3406202392821375
22 21545888897092560
23 136655834260685220
24 868897745157965328

List of values

[0, 2, 9, 43, 218, 1155, 6324, 35511, 203412, 1184040, 6983925, 41652468, 250763464, 1521935948, 9301989144, 57203999295, 353701790376, 2197600497330, 13713291247635, 85907187607395, 540072341320050, 3406202392821375, 21545888897092560, 136655834260685220, 868897745157965328]

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

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