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 | -3 |
| 2 | -9 |
| 3 | 81 |
| 4 | 1215 |
| 5 | -40095 |
| 6 | -2525985 |
| 7 | 325852065 |
| 8 | 83092276575 |
| 9 | -42626337882975 |
| 10 | -43606743654283425 |
| 11 | 89350217747626737825 |
| 12 | 365889141676531491393375 |
| 13 | -2997729737755822508985921375 |
| 14 | -49111806293653640164716349886625 |
| 15 | 1609344780436736134557590069434814625 |