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.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 16 |
| 3 | 110 |
| 4 | 770 |
| 5 | 5512 |
| 6 | 40066 |
| 7 | 294484 |
| 8 | 2182850 |
| 9 | 16288430 |
| 10 | 122198926 |
| 11 | 920820578 |
| 12 | 6964483628 |
| 13 | 52840433000 |
| 14 | 401990254180 |
| 15 | 3065365241440 |
| 16 | 23422905551018 |
| 17 | 179302895759782 |
| 18 | 1374785979255880 |
| 19 | 10556280995419090 |
| 20 | 81161958814162700 |
| 21 | 624750086745027388 |