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 | -1 |
| 2 | -2 |
| 3 | 3 |
| 4 | 248 |
| 5 | 5655 |
| 6 | 62064 |
| 7 | -3516625 |
| 8 | -376936064 |
| 9 | -21890186577 |
| 10 | -495165203200 |
| 11 | 96687112380639 |
| 12 | 20607024735783936 |
| 13 | 2471270260977141767 |
| 14 | 142697263160045590528 |
| 15 | -25986252776953159328625 |
| 16 | -11860424645318274482077696 |
| 17 | -2719428501410438623907546529 |
| 18 | -372732332273232481973818294272 |