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 | 3 |
| 3 | 19 |
| 4 | 201 |
| 5 | 2841 |
| 6 | 48245 |
| 7 | 939863 |
| 8 | 20341201 |
| 9 | 487875964 |
| 10 | 12830282835 |
| 11 | 370205055144 |
| 12 | 11629998323185 |
| 13 | 396693714869323 |
| 14 | 14593231979817751 |
| 15 | 576427808563042857 |