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 | 0 |
| 2 | -2 |
| 3 | -2 |
| 4 | 0 |
| 5 | 0 |
| 6 | -12 |
| 7 | -88 |
| 8 | -608 |
| 9 | -4664 |
| 10 | -40032 |
| 11 | -381200 |
| 12 | -3993520 |
| 13 | -45685472 |
| 14 | -566975456 |
| 15 | -7589393568 |
| 16 | -109019255360 |
| 17 | -1673050977024 |
| 18 | -27321358963904 |
| 19 | -473094230383616 |
| 20 | -8659054324278528 |
| 21 | -167044915214322816 |
| 22 | -3387793305708038400 |
| 23 | -72061754672510128384 |