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 | 2 |
| 3 | -3 |
| 4 | -6 |
| 5 | 45 |
| 6 | 11 |
| 7 | -1372 |
| 8 | 4298 |
| 9 | 59244 |
| 10 | -573463 |
| 11 | -2432023 |
| 12 | 75984243 |
| 13 | -136498141 |
| 14 | -10881169822 |
| 15 | 100704750342 |
| 16 | 1514280063802 |
| 17 | -36086469752977 |
| 18 | -102642110690866 |
| 19 | 11883894518252419 |
| 20 | -77863424962770751 |
| 21 | -3705485804176583500 |
| 22 | 71306510264347489177 |