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 | 4 |
| 2 | -6 |
| 3 | 32 |
| 4 | -170 |
| 5 | -228 |
| 6 | 43764 |
| 7 | -1498880 |
| 8 | 43826598 |
| 9 | -1249865260 |
| 10 | 35978752876 |
| 11 | -1053020066976 |
| 12 | 31153402105852 |
| 13 | -914722450924436 |
| 14 | 25562930671296360 |
| 15 | -604802562457466880 |
| 16 | 5868775340572918534 |
| 17 | 684246820455046681380 |
| 18 | -78372285809430441261828 |