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 | -496 |
| 3 | -19619 |
| 4 | -261888 |
| 5 | -1952101 |
| 6 | -10073600 |
| 7 | -40337223 |
| 8 | -134152192 |
| 9 | -387158345 |
| 10 | -998951424 |
| 11 | -2353753387 |
| 12 | -5143003136 |
| 13 | -10537390509 |
| 14 | -20392611328 |
| 15 | -37369617551 |
| 16 | -64424509440 |
| 17 | -101408007313 |
| 18 | -129639813632 |