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 | 294 |
| 4 | 37800 |
| 5 | 19373760 |
| 6 | 39687459840 |
| 7 | 325139829719040 |
| 8 | 10654345790226432000 |
| 9 | 1396491759480328106803200 |
| 10 | 732164571206732295657278668800 |
| 11 | 1535460761275478347250381697633484800 |
| 12 | 12880379193826999985837000446453418557440000 |