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.

A212807 Number of ways to place 2n points on a 2n X 2n square array of points such that no three points are collinear and the configuration has 90-degree rotational symmetry.

Table of values

n a(n)
1 1
2 1
3 3
4 4
5 7
6 4
7 13
8 13
9 7
10 16
11 8
12 23
13 36
14 58
15 92
16 101
17 172
18 281
19 337
20 541
21 746

List of values

[1, 1, 3, 4, 7, 4, 13, 13, 7, 16, 8, 23, 36, 58, 92, 101, 172, 281, 337, 541, 746]