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 | 1 |
| 2 | 8 |
| 3 | 54 |
| 4 | 0 |
| 5 | -12500 |
| 6 | -373248 |
| 7 | -6588344 |
| 8 | 0 |
| 9 | 6198727824 |
| 10 | 320000000000 |
| 11 | 9129973459552 |
| 12 | 0 |
| 13 | -19384006821904192 |
| 14 | -1422336873671426048 |
| 15 | -56050417968750000000 |
| 16 | 0 |
| 17 | 211773507042902211629312 |
| 18 | 20145360934551827238617088 |
| 19 | 1012950863698080557631477248 |
| 20 | 0 |
| 21 | -5982809106827246101894271407104 |