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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.

A256644 Numbers of alternating permutations where numbers at odd positions and even positions are monotone respectively.

Table of values

n a(n)
0 1
1 1
2 1
3 2
4 5
5 6
6 9
7 12
8 21
9 30
10 58
11 86
12 176
13 266
14 563
15 860
16 1861
17 2862
18 6294
19 9726
20 21660
21 33594
22 75584
23 117574
24 266800
25 416026
26 950914
27 1485802
28 3417342
29 5348882
30 12369287
31 19389692
32 45052517
33 70715342
34 165002462
35 259289582
36 607283492
37 955277402
38 2244901892

List of values

[1, 1, 1, 2, 5, 6, 9, 12, 21, 30, 58, 86, 176, 266, 563, 860, 1861, 2862, 6294, 9726, 21660, 33594, 75584, 117574, 266800, 416026, 950914, 1485802, 3417342, 5348882, 12369287, 19389692, 45052517, 70715342, 165002462, 259289582, 607283492, 955277402, 2244901892]

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

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