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 | -10 |
| 3 | -2 |
| 4 | 488 |
| 5 | 4088 |
| 6 | -9968 |
| 7 | -730480 |
| 8 | -9751936 |
| 9 | -11540096 |
| 10 | 2480655104 |
| 11 | 62522038016 |
| 12 | 680469314560 |
| 13 | -8292439149568 |
| 14 | -606011029669888 |
| 15 | -15765339965278208 |
| 16 | -183530875864317952 |
| 17 | 4164677242501038080 |
| 18 | 318357069130977181696 |
| 19 | 10359690304436314505216 |
| 20 | 176911847384965046337536 |