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 | 2 |
| 3 | 5 |
| 4 | 17 |
| 5 | 80 |
| 6 | 525 |
| 7 | 4839 |
| 8 | 62936 |
| 9 | 1158785 |
| 10 | 30277579 |
| 11 | 1124649526 |
| 12 | 59465788597 |
| 13 | 4480380804517 |
| 14 | 481401971074410 |
| 15 | 73812092299235769 |
| 16 | 16158739669470307453 |
| 17 | 5052972095683109687920 |
| 18 | 2257981256268589345121153 |