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 | 7 |
| 4 | 56 |
| 5 | 2212 |
| 6 | 2595782 |
| 7 | 3374959180831 |
| 8 | 5695183504489239067484387 |
| 9 | 16217557574922386301420531277071365103168734284282 |