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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 119 |
| 6 | 708 |
| 7 | 4914 |
| 8 | 38979 |
| 9 | 347829 |
| 10 | 3448722 |
| 11 | 37613451 |
| 12 | 447524466 |
| 13 | 5768361795 |
| 14 | 80070563433 |
| 15 | 1190848464594 |
| 16 | 18891604332045 |
| 17 | 318427172178204 |
| 18 | 5682965018856093 |
| 19 | 107058447534630429 |
| 20 | 2122967250258006555 |
| 21 | 44203325864880537180 |
| 22 | 964206345760838800371 |