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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 34 |
| 4 | 313 |
| 5 | 3711 |
| 6 | 54121 |
| 7 | 937924 |
| 8 | 18831569 |
| 9 | 429794605 |
| 10 | 10987654321 |
| 11 | 310989720966 |
| 12 | 9652968253897 |
| 13 | 326011399456939 |
| 14 | 11901025061692313 |
| 15 | 466937872906120456 |
| 16 | 19594541482740368161 |
| 17 | 875711370981239308953 |
| 18 | 41524755927216069067489 |
| 19 | 2082225625247428808306410 |