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 | 2 |
| 1 | -4 |
| 2 | 40 |
| 3 | -544 |
| 4 | 8540 |
| 5 | -145720 |
| 6 | 2625648 |
| 7 | -49161024 |
| 8 | 947069352 |
| 9 | -18650752400 |
| 10 | 373773754912 |
| 11 | -7598155324032 |
| 12 | 156294309718944 |
| 13 | -3247203559571136 |
| 14 | 68042170392274560 |
| 15 | -1436308791802028544 |
| 16 | 30514944039812500572 |