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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.

A263965 Number of (1+1)X(n+1) arrays of permutations of 0..n*2+1 with each element having index change (+-,+-) 0,0 1,1 or 1,2.

Table of values

n a(n)
1 4
2 20
3 108
4 465
5 2265
6 10920
7 52752
8 253176
9 1221305
10 5885873
11 28368956
12 136712788
13 658952404
14 3175970497
15 15307435585
16 73778034832
17 355593913600
18 1713880597360
19 8260513454657
20 39813787812289
21 191893397639092
22 924882430123988

List of values

[4, 20, 108, 465, 2265, 10920, 52752, 253176, 1221305, 5885873, 28368956, 136712788, 658952404, 3175970497, 15307435585, 73778034832, 355593913600, 1713880597360, 8260513454657, 39813787812289, 191893397639092, 924882430123988]

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

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