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 | 9 |
| 3 | 252 |
| 4 | 18396 |
| 5 | 2317896 |
| 6 | 584109792 |
| 7 | 200933768448 |
| 8 | 117546254542080 |
| 9 | 88982514688354560 |
| 10 | 100906171656594071040 |
| 11 | 134407020646583302625280 |
| 12 | 274727950201616270566072320 |
| 13 | 603852034543152562704226959360 |
| 14 | 1869525898945600334132286666178560 |