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 | 2 |
| 4 | 6 |
| 5 | 22 |
| 6 | 98 |
| 7 | 522 |
| 8 | 3262 |
| 9 | 23486 |
| 10 | 191802 |
| 11 | 1753618 |
| 12 | 17755382 |
| 13 | 197282022 |
| 14 | 2387112466 |
| 15 | 31249472282 |
| 16 | 440096734638 |
| 17 | 6635304614542 |
| 18 | 106638824162282 |
| 19 | 1819969265702946 |