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 | 9 |
| 2 | 45 |
| 3 | 285 |
| 4 | 1695 |
| 5 | 10317 |
| 6 | 62349 |
| 7 | 377739 |
| 8 | 2286648 |
| 9 | 13846117 |
| 10 | 83833256 |
| 11 | 507596153 |
| 12 | 3073376281 |
| 13 | 18608642427 |
| 14 | 112671254094 |
| 15 | 682200039446 |
| 16 | 4130572919575 |
| 17 | 25009722123505 |
| 18 | 151428434581516 |
| 19 | 916866281219258 |