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 | 0 |
| 1 | 1 |
| 2 | 15 |
| 3 | 1268 |
| 4 | 317294 |
| 5 | 175542694 |
| 6 | 181641609214 |
| 7 | 315309390376056 |
| 8 | 850661260866748728 |
| 9 | 3370191684116333977872 |
| 10 | 18768704088141613880906736 |
| 11 | 141902519646656406912522712848 |
| 12 | 1415862822521619228707500717132224 |
| 13 | 18210234893009450819658863637633454608 |