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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 9 |
| 6 | 30 |
| 7 | 81 |
| 8 | 242 |
| 9 | 838 |
| 10 | 2799 |
| 11 | 9365 |
| 12 | 33616 |
| 13 | 122937 |
| 14 | 449698 |
| 15 | 1696724 |
| 16 | 6558855 |
| 17 | 25559806 |
| 18 | 101294687 |
| 19 | 409363758 |
| 20 | 1673735259 |
| 21 | 6928460475 |
| 22 | 29115833976 |
| 23 | 123835124242 |
| 24 | 532449210893 |
| 25 | 2317382872404 |
| 26 | 10199542298725 |
| 27 | 45345006540851 |
| 28 | 203704505953902 |
| 29 | 924427259637953 |
| 30 | 4234544300812834 |