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 | 1 |
| 3 | -10 |
| 4 | 157 |
| 5 | -3136 |
| 6 | 77509 |
| 7 | -2288896 |
| 8 | 78824953 |
| 9 | -3105906688 |
| 10 | 137925180361 |
| 11 | -6818997285376 |
| 12 | 371578940493589 |
| 13 | -22130352562929664 |
| 14 | 1430368670554859533 |
| 15 | -99722125119137591296 |
| 16 | 7459992570265962997489 |
| 17 | -596072767690463855509504 |
| 18 | 50666927756525446827810961 |