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 | 347830 |
| 10 | 3448742 |
| 11 | 37613781 |
| 12 | 447529736 |
| 13 | 5768447194 |
| 14 | 80071991461 |
| 15 | 1190873311644 |
| 16 | 18892055757622 |
| 17 | 318435746208625 |
| 18 | 5683135262448470 |
| 19 | 107061979121943224 |
| 20 | 2123043715555546099 |
| 21 | 44205051951114604550 |
| 22 | 964246919041476700230 |