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 | 1 |
| 3 | 1 |
| 4 | 97 |
| 5 | 601 |
| 6 | 2161 |
| 7 | 5881 |
| 8 | 1303681 |
| 9 | 14723857 |
| 10 | 90770401 |
| 11 | 402581521 |
| 12 | 139389608161 |
| 13 | 2284512533161 |
| 14 | 19946635524817 |
| 15 | 122623661651401 |
| 16 | 57728368477678081 |
| 17 | 1240234284406887841 |
| 18 | 14010634784751445441 |
| 19 | 110117252571345122977 |