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) |
|---|---|
| 2 | 1 |
| 3 | 9 |
| 4 | 63 |
| 5 | 447 |
| 6 | 3447 |
| 7 | 29367 |
| 8 | 276327 |
| 9 | 2856807 |
| 10 | 32250087 |
| 11 | 395130087 |
| 12 | 5225062887 |
| 13 | 74201293287 |
| 14 | 1126567808487 |
| 15 | 18213512883687 |
| 16 | 312440245683687 |
| 17 | 5668674457011687 |
| 18 | 108462341176755687 |
| 19 | 2182831421832627687 |
| 20 | 46096712669420979687 |