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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 4 |
| 4 | 75 |
| 5 | 1296 |
| 6 | 24010 |
| 7 | 491520 |
| 8 | 11160261 |
| 9 | 280000000 |
| 10 | 7716919716 |
| 11 | 232190115840 |
| 12 | 7582217051695 |
| 13 | 267271301197824 |
| 14 | 10120214355468750 |
| 15 | 409827566090715136 |
| 16 | 17679671788737097545 |
| 17 | 809596873977295011840 |
| 18 | 39228032245196478804616 |
| 19 | 2005401600000000000000000 |
| 20 | 107880615499838355594014931 |