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 | 0 |
| 3 | 1 |
| 4 | -8 |
| 5 | -35 |
| 6 | 627 |
| 7 | -20965 |
| 8 | -761577 |
| 9 | 72676071 |
| 10 | -3470319335 |
| 11 | -4692803610731 |
| 12 | 418741237461085 |
| 13 | 180890439981934931 |
| 14 | -2244276655546627749157 |
| 15 | -764583000726654718413105 |
| 16 | 12199909914654265034887926688 |
| 17 | -296226554714255082163286916350895 |
| 18 | -1802246724473363548181037369907741088 |