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) |
|---|---|
| 3 | 1 |
| 4 | -6 |
| 5 | 35 |
| 6 | -235 |
| 7 | 1834 |
| 8 | -16352 |
| 9 | 164044 |
| 10 | -1830630 |
| 11 | 22513326 |
| 12 | -302700926 |
| 13 | 4419167532 |
| 14 | -69637654996 |
| 15 | 1178377833424 |
| 16 | -21315571470320 |
| 17 | 410529985172400 |
| 18 | -8388475139138320 |
| 19 | 181270810764205440 |
| 20 | -4130796696683135280 |
| 21 | 99008773205008777760 |
| 22 | -2490134250475836315120 |