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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.

A037223 Number of solutions to non-attacking rooks problem on n X n board that are invariant under 180-degree rotation.

Table of values

n a(n)
0 1
1 1
2 2
3 2
4 8
5 8
6 48
7 48
8 384
9 384
10 3840
11 3840
12 46080
13 46080
14 645120
15 645120
16 10321920
17 10321920
18 185794560
19 185794560
20 3715891200
21 3715891200
22 81749606400
23 81749606400
24 1961990553600
25 1961990553600
26 51011754393600
27 51011754393600
28 1428329123020800
29 1428329123020800

List of values

[1, 1, 2, 2, 8, 8, 48, 48, 384, 384, 3840, 3840, 46080, 46080, 645120, 645120, 10321920, 10321920, 185794560, 185794560, 3715891200, 3715891200, 81749606400, 81749606400, 1961990553600, 1961990553600, 51011754393600, 51011754393600, 1428329123020800, 1428329123020800]

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

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