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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.

A201222 Number of ways to place k non-attacking knights on a 2 X n horizontal cylinder, summed over all k>=0.

Table of values

n a(n)
1 3
2 9
3 18
4 81
5 123
6 324
7 843
8 2401
9 5778
10 15129
11 39603
12 104976
13 271443
14 710649
15 1860498
16 4879681
17 12752043
18 33385284
19 87403803
20 228886641
21 599074578
22 1568397609
23 4106118243
24 10750371856
25 28143753123
26 73681302249
27 192900153618
28 505022001201
29 1322157322203

List of values

[3, 9, 18, 81, 123, 324, 843, 2401, 5778, 15129, 39603, 104976, 271443, 710649, 1860498, 4879681, 12752043, 33385284, 87403803, 228886641, 599074578, 1568397609, 4106118243, 10750371856, 28143753123, 73681302249, 192900153618, 505022001201, 1322157322203]

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

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