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.

A234009 Free polyominoes with 4n squares, having 90-degree rotational symmetry about a square corner.

Table of values

n a(n)
1 1
2 1
3 4
4 10
5 35
6 114
7 403
8 1432
9 5239
10 19271
11 71820
12 269417
13 1017920
14 3864879

List of values

[1, 1, 4, 10, 35, 114, 403, 1432, 5239, 19271, 71820, 269417, 1017920, 3864879]