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 | 0 |
| 2 | 1 |
| 3 | 9 |
| 4 | 96 |
| 5 | 1250 |
| 6 | 19440 |
| 7 | 352947 |
| 8 | 7340032 |
| 9 | 172186884 |
| 10 | 4500000000 |
| 11 | 129687123005 |
| 12 | 4086546038784 |
| 13 | 139788510734886 |
| 14 | 5159146026151936 |
| 15 | 204350482177734375 |
| 16 | 8646911284551352320 |
| 17 | 389289535005334947848 |
| 18 | 18580248257778920521728 |
| 19 | 937146152681201173795569 |