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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.

A197465 Number of free tetrakis polyaboloes (poly-[4.8^2]-tiles) with n cells, allowing holes, where division into tetrakis cells (triangular quarters of square grid cells) is significant.

Table of values

n a(n)
1 1
2 2
3 2
4 6
5 8
6 22
7 42
8 112
9 252
10 650
11 1584
12 4091
13 10369
14 26938
15 69651
16 182116
17 476272
18 1253067
19 3302187
20 8733551
21 23142116
22 61477564
23 163612714
24 436278921
25 1165218495
26 3117021788
27 8349892686
28 22397754046
29 60153261611

List of values

[1, 2, 2, 6, 8, 22, 42, 112, 252, 650, 1584, 4091, 10369, 26938, 69651, 182116, 476272, 1253067, 3302187, 8733551, 23142116, 61477564, 163612714, 436278921, 1165218495, 3117021788, 8349892686, 22397754046, 60153261611]

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

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