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 | 9 |
| 3 | 62 |
| 4 | 689 |
| 5 | 7322 |
| 6 | 69369 |
| 7 | 616982 |
| 8 | 5422049 |
| 9 | 48197042 |
| 10 | 433434729 |
| 11 | 3913915502 |
| 12 | 35311723409 |
| 13 | 317999340362 |
| 14 | 2860994944089 |
| 15 | 25738114039622 |
| 16 | 231602961592769 |
| 17 | 2084457277181282 |
| 18 | 18761300850805449 |
| 19 | 168858054223133342 |
| 20 | 1519730933499158129 |
| 21 | 13677470410291063802 |