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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 8 |
| 5 | 27 |
| 6 | 110 |
| 7 | 538 |
| 8 | 3149 |
| 9 | 21622 |
| 10 | 172348 |
| 11 | 1549896 |
| 12 | 15401144 |
| 13 | 168011252 |
| 14 | 2003304293 |
| 15 | 25928878272 |
| 16 | 361788001015 |
| 17 | 5411160126367 |
| 18 | 86353882249911 |
| 19 | 1464841397585335 |
| 20 | 26323224850512719 |
| 21 | 499551889319197565 |