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 | 2 |
| 4 | 9 |
| 5 | 30 |
| 6 | 110 |
| 7 | 387 |
| 8 | 1419 |
| 9 | 5185 |
| 10 | 19225 |
| 11 | 71634 |
| 12 | 269250 |
| 13 | 1017260 |
| 14 | 3864267 |
| 15 | 14742260 |
| 16 | 56470053 |
| 17 | 217052829 |
| 18 | 836878982 |