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) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 18 |
| 3 | -288 |
| 4 | -1890 |
| 5 | 41472 |
| 6 | 324324 |
| 7 | -7962624 |
| 8 | -67343562 |
| 9 | 1751777280 |
| 10 | 15489019260 |
| 11 | -417368899584 |
| 12 | -3797625904020 |
| 13 | 104791699095552 |
| 14 | 972776481568200 |
| 15 | -27305722735755264 |
| 16 | -257250740550710490 |
| 17 | 7314721255213498368 |
| 18 | 69699818292739559820 |