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 | -2 |
| 2 | 0 |
| 3 | 8 |
| 4 | 16 |
| 5 | -64 |
| 6 | -576 |
| 7 | -1152 |
| 8 | 12800 |
| 9 | 136704 |
| 10 | 422912 |
| 11 | -4464640 |
| 12 | -72626176 |
| 13 | -413966336 |
| 14 | 1805123584 |
| 15 | 64448004096 |
| 16 | 651340611584 |
| 17 | 1132294045696 |
| 18 | -73000566390784 |
| 19 | -1332193006190592 |
| 20 | -10293724166750208 |
| 21 | 56984418960539648 |
| 22 | 3042980275005947904 |
| 23 | 46913652420264329216 |