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.

A348404 Number of achiral polyomino rings of length 2n with twofold rotational symmetry.

Table of values

n a(n)
1 0
2 1
3 0
4 1
5 1
6 3
7 2
8 6
9 4
10 14
11 8
12 30
13 18
14 71
15 40
16 155
17 89
18 358
19 198
20 786
21 445
22 1808
23 998
24 3994
25 2250
26 9158
27 5068

List of values

[0, 1, 0, 1, 1, 3, 2, 6, 4, 14, 8, 30, 18, 71, 40, 155, 89, 358, 198, 786, 445, 1808, 998, 3994, 2250, 9158, 5068]