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 | 3 |
| 5 | 7 |
| 6 | 75 |
| 7 | 984 |
| 8 | 105831 |
| 9 | 35494648 |
| 10 | 53493557150 |
| 11 | 250087643676776 |
| 12 | 4520743153498327817 |
| 13 | 272584534800111470995411 |