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 | 1 |
| 3 | 2 |
| 4 | 330 |
| 5 | 714 |
| 6 | 13530 |
| 7 | 192660 |
| 8 | 512820 |
| 9 | 4601310 |
| 10 | 863815050 |
| 11 | 262428279750 |
| 12 | 2169289182060 |
| 13 | 2169289182060 |
| 14 | 2169289182060 |
| 15 | 4646092391146085880 |