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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 54 |
| 5 | 750 |
| 6 | 11250 |
| 7 | 360150 |
| 8 | 123531450 |
| 9 | 3088286250 |
| 10 | 64854011250 |
| 11 | 77201350992150 |
| 12 | 65389544290351050 |
| 13 | 32637304517036749530 |
| 14 | 2121424793607388719450 |
| 15 | 163349709107768931397650 |