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 | 1 |
| 2 | -4 |
| 3 | -10 |
| 4 | 84 |
| 5 | 265 |
| 6 | -2604 |
| 7 | -8900 |
| 8 | 94692 |
| 9 | 337940 |
| 10 | -3767312 |
| 11 | -13812674 |
| 12 | 158785964 |
| 13 | 593029550 |
| 14 | -6967201736 |
| 15 | -26372738120 |
| 16 | 314904180100 |
| 17 | 1204230041900 |
| 18 | -14560722724912 |
| 19 | -56130528427400 |
| 20 | 685514219386576 |
| 21 | 2659770565898729 |
| 22 | -32749512944380172 |