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 | 7 |
| 3 | 54 |
| 4 | 553 |
| 5 | 7100 |
| 6 | 109863 |
| 7 | 1991752 |
| 8 | 41426257 |
| 9 | 972602640 |
| 10 | 25447064743 |
| 11 | 734276705888 |
| 12 | 23166635069241 |
| 13 | 793426715543488 |
| 14 | 29316839407495111 |
| 15 | 1162492244159875200 |
| 16 | 49240280161094287777 |
| 17 | 2218952409252783579392 |