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) |
|---|---|
| 1 | 2 |
| 2 | 3 |
| 3 | 10 |
| 4 | 105 |
| 5 | 770 |
| 6 | 15015 |
| 7 | 170170 |
| 8 | 4849845 |
| 9 | 6760390 |
| 10 | 3234846615 |
| 11 | 200560490130 |
| 12 | 72752334655 |
| 13 | 4680773285034 |
| 14 | 284407855036305 |
| 15 | 614889782588491410 |
| 16 | 465559406817000639 |
| 17 | 44715356980330526490 |
| 18 | 19548063559901161830545 |