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.

A263738 Number of length n arrays of permutations of 0..n-1 with each element moved by -2 to 2 places and equal numbers of elements moved upwards and downwards.

Table of values

n a(n)
1 1
2 2
3 4
4 10
5 19
6 43
7 90
8 202
9 434
10 971
11 2133
12 4780
13 10634
14 23918
15 53667
16 121159
17 273464
18 619510
19 1404284
20 3190779
21 7256305
22 16529258
23 37686110
24 86028558
25 196547581
26 449479587
27 1028674074
28 2356054490
29 5399827384
30 12383951473
31 28417821421

List of values

[1, 2, 4, 10, 19, 43, 90, 202, 434, 971, 2133, 4780, 10634, 23918, 53667, 121159, 273464, 619510, 1404284, 3190779, 7256305, 16529258, 37686110, 86028558, 196547581, 449479587, 1028674074, 2356054490, 5399827384, 12383951473, 28417821421]

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

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