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 | 4 |
| 4 | 2 |
| 5 | -74 |
| 6 | -916 |
| 7 | -8672 |
| 8 | -73564 |
| 9 | -542852 |
| 10 | -2595016 |
| 11 | 18348496 |
| 12 | 906083672 |
| 13 | 21021502984 |
| 14 | 406255974032 |
| 15 | 7157641045696 |
| 16 | 116383645516784 |
| 17 | 1681549859135248 |
| 18 | 18311613681506336 |
| 19 | -3332917116147392 |