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 | -2 |
| 3 | -3 |
| 4 | 44 |
| 5 | 245 |
| 6 | -2346 |
| 7 | -33278 |
| 8 | 186808 |
| 9 | 6888555 |
| 10 | -6774910 |
| 11 | -1986368439 |
| 12 | -10227075420 |
| 13 | 738830661296 |
| 14 | 10363304656782 |
| 15 | -327255834908715 |
| 16 | -9380517430358288 |
| 17 | 152180429032236325 |
| 18 | 9132761207739810618 |
| 19 | -46897839494116200918 |
| 20 | -9833058047657527541220 |