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 | 0 |
| 2 | 7 |
| 3 | -17 |
| 4 | 166 |
| 5 | -931 |
| 6 | 8333 |
| 7 | -67902 |
| 8 | 668341 |
| 9 | -6733957 |
| 10 | 74909152 |
| 11 | -875130273 |
| 12 | 10931723505 |
| 13 | -143624036492 |
| 14 | 1989841289619 |
| 15 | -28881136161245 |
| 16 | 438657928012966 |
| 17 | -6948176832355895 |
| 18 | 114571387874994353 |
| 19 | -1962292996833874918 |
| 20 | 34849770255925089153 |
| 21 | -640681440719312240225 |
| 22 | 12174584322610783966760 |