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 | 0 |
| 2 | 6 |
| 3 | -240 |
| 4 | 9540 |
| 5 | -415590 |
| 6 | 20134590 |
| 7 | -1082674404 |
| 8 | 64221641820 |
| 9 | -4173853100670 |
| 10 | 295282282905720 |
| 11 | -22605059036265420 |
| 12 | 1862664627479732076 |
| 13 | -164425432052147568120 |
| 14 | 15483794266369962976170 |
| 15 | -1549617160894627918342620 |
| 16 | 164264715996348003982855020 |