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 | 1 |
| 2 | 5 |
| 3 | 56 |
| 4 | 501 |
| 5 | 4006 |
| 6 | 27950 |
| 7 | 214689 |
| 8 | 1696781 |
| 9 | 13205354 |
| 10 | 101698212 |
| 11 | 782267786 |
| 12 | 6048166230 |
| 13 | 46799177380 |
| 14 | 361683136647 |
| 15 | 2793722300087 |
| 16 | 21583392631817 |
| 17 | 166790059833039 |
| 18 | 1288885349447958 |
| 19 | 9959188643348952 |
| 20 | 76953117224941654 |
| 21 | 594617039453764617 |
| 22 | 4594660583890506956 |