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 | -2 |
| 2 | -8 |
| 3 | -60 |
| 4 | -600 |
| 5 | -7152 |
| 6 | -96456 |
| 7 | -1430544 |
| 8 | -22933920 |
| 9 | -393013280 |
| 10 | -7144207808 |
| 11 | -137001926144 |
| 12 | -2760226854816 |
| 13 | -58242464679360 |
| 14 | -1283886660610560 |
| 15 | -29506641823939200 |
| 16 | -705788634473952000 |
| 17 | -17544801385483584000 |
| 18 | -452659831142363014400 |