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 | 3 |
| 1 | 0 |
| 2 | 98 |
| 3 | -147 |
| 4 | 4802 |
| 5 | -12005 |
| 6 | 242501 |
| 7 | -823543 |
| 8 | 12470794 |
| 9 | -52236156 |
| 10 | 651422513 |
| 11 | -3170640550 |
| 12 | 34479274781 |
| 13 | -187281090087 |
| 14 | 1844845851219 |
| 15 | -10866257878532 |
| 16 | 99574220123994 |
| 17 | -622844082757799 |
| 18 | 5411583422123774 |
| 19 | -35398496841207857 |
| 20 | 295686947739197077 |
| 21 | -1999693932903249919 |