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 | 2 |
| 1 | 10 |
| 2 | 70 |
| 3 | 462 |
| 4 | 3018 |
| 5 | 19922 |
| 6 | 133262 |
| 7 | 901654 |
| 8 | 6155410 |
| 9 | 42306714 |
| 10 | 292240854 |
| 11 | 2026154846 |
| 12 | 14085427802 |
| 13 | 98109713506 |
| 14 | 684326588446 |
| 15 | 4778079088038 |
| 16 | 33385518460194 |
| 17 | 233393453440298 |
| 18 | 1632228295176038 |
| 19 | 11417968671701230 |