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 | 4 |
| 2 | 56 |
| 3 | 1672 |
| 4 | 85904 |
| 5 | 6741544 |
| 6 | 749040472 |
| 7 | 111786940612 |
| 8 | 21558649749088 |
| 9 | 5215883627856592 |
| 10 | 1546429233541304456 |
| 11 | 551278120123210461436 |
| 12 | 232603216443181020788944 |
| 13 | 114634034948809175011787176 |