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.

A256456 Number of simple 2n-gons with only right angles, disregarding edge lengths.

Table of values

n a(n)
1 0
2 1
3 1
4 4
5 8
6 29
7 79
8 280
9 912
10 3260
11 11410
12 41272
13 148976
14 544802
15 1997499
16 7372080
17 27299360
18 101520714
19 378721134
20 1417339352
21 5318837680
22 20012141478
23 75473438326
24 285268537424
25 1080433781728
26 4099860518208
27 15585111068644
28 59343308199216
29 226312777319776

List of values

[0, 1, 1, 4, 8, 29, 79, 280, 912, 3260, 11410, 41272, 148976, 544802, 1997499, 7372080, 27299360, 101520714, 378721134, 1417339352, 5318837680, 20012141478, 75473438326, 285268537424, 1080433781728, 4099860518208, 15585111068644, 59343308199216, 226312777319776]