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 | 40 |
| 3 | 793 |
| 4 | 12800 |
| 5 | 193721 |
| 6 | 2886520 |
| 7 | 42999713 |
| 8 | 642355200 |
| 9 | 9617422321 |
| 10 | 144167168200 |
| 11 | 2162192792233 |
| 12 | 32433400563200 |
| 13 | 486521516676521 |
| 14 | 7298047169453080 |
| 15 | 109472483776866353 |
| 16 | 1642098503032012800 |
| 17 | 24631532723767204321 |
| 18 | 369473147671033293160 |
| 19 | 5542096617629211606073 |
| 20 | 83131435057615545920000 |