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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.

A245233 Number of permutations generated by passing an ordered sequence of length n through a stack of depth 2 and an infinite stack in series.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 24
5 114
6 592
7 3216
8 17904
9 101198
10 578208
11 3332136
12 19343408
13 113017332
14 664168160
15 3923729280
16 23291913440
17 138872375958
18 831321465408
19 4994806458040
20 30111586314800
21 182094123983660
22 1104331746746208
23 6715050373394528
24 40931670125150624
25 250065092876686924
26 1530948705125205952
27 9391164635349135184

List of values

[1, 1, 2, 6, 24, 114, 592, 3216, 17904, 101198, 578208, 3332136, 19343408, 113017332, 664168160, 3923729280, 23291913440, 138872375958, 831321465408, 4994806458040, 30111586314800, 182094123983660, 1104331746746208, 6715050373394528, 40931670125150624, 250065092876686924, 1530948705125205952, 9391164635349135184]

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

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