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 | 0 |
| 1 | -9 |
| 2 | 432 |
| 3 | -20304 |
| 4 | 953865 |
| 5 | -44811360 |
| 6 | 2105180064 |
| 7 | -98898651657 |
| 8 | 4646131447824 |
| 9 | -218269279396080 |
| 10 | 10254010000167945 |
| 11 | -481720200728497344 |
| 12 | 22630595424239207232 |
| 13 | -1063156264738514242569 |
| 14 | 49945713847285930193520 |
| 15 | -2346385394557700204852880 |