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 | 38982 |
| 9 | 347873 |
| 10 | 3449332 |
| 11 | 37621965 |
| 12 | 447648482 |
| 13 | 5770250935 |
| 14 | 80100822074 |
| 15 | 1191358479790 |
| 16 | 18900647287550 |
| 17 | 318595643201902 |
| 18 | 5686258136269396 |
| 19 | 107125880782919395 |
| 20 | 2124411456922993308 |
| 21 | 44235624533456911964 |
| 22 | 964959480961869203870 |