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 | 2 |
| 2 | -5 |
| 3 | 22 |
| 4 | -115 |
| 5 | 646 |
| 6 | -3822 |
| 7 | 23496 |
| 8 | -148368 |
| 9 | 955822 |
| 10 | -6256273 |
| 11 | 41480668 |
| 12 | -277954706 |
| 13 | 1879118354 |
| 14 | -12800031737 |
| 15 | 87758481546 |
| 16 | -605091552753 |
| 17 | 4192829686338 |
| 18 | -29180958305391 |
| 19 | 203887504096188 |
| 20 | -1429568781831693 |
| 21 | 10055261467844862 |
| 22 | -70929518958227340 |