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 | 2 |
| 2 | 8 |
| 3 | 58 |
| 4 | 462 |
| 5 | 3782 |
| 6 | 31436 |
| 7 | 264134 |
| 8 | 2237640 |
| 9 | 19079574 |
| 10 | 163538472 |
| 11 | 1407813438 |
| 12 | 12163015662 |
| 13 | 105407889930 |
| 14 | 915913267652 |
| 15 | 7976914859210 |
| 16 | 69613332125342 |
| 17 | 608590829593638 |
| 18 | 5329041851925256 |
| 19 | 46729591602635246 |
| 20 | 410291878420535354 |
| 21 | 3606612469259086834 |