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 | 4 |
| 2 | 0 |
| 3 | -16 |
| 4 | 16 |
| 5 | 120 |
| 6 | -128 |
| 7 | -928 |
| 8 | 1056 |
| 9 | 7572 |
| 10 | -8960 |
| 11 | -63408 |
| 12 | 77248 |
| 13 | 540504 |
| 14 | -672000 |
| 15 | -4665824 |
| 16 | 5888832 |
| 17 | 40656072 |
| 18 | -51913728 |
| 19 | -356835664 |
| 20 | 459890400 |
| 21 | 3150052992 |
| 22 | -4090609024 |
| 23 | -27939033312 |
| 24 | 36509767552 |
| 25 | 248772971228 |
| 26 | -326815190784 |
| 27 | -2222432164768 |
| 28 | 2932886151552 |
| 29 | 19910399315736 |