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 | 10 |
| 4 | -4 |
| 5 | -42 |
| 6 | -258 |
| 7 | 306 |
| 8 | 5980 |
| 9 | 3142 |
| 10 | 61730 |
| 11 | -794334 |
| 12 | -3299074 |
| 13 | -8459830 |
| 14 | 40220390 |
| 15 | 1550926110 |
| 16 | 1631691740 |
| 17 | 43693916390 |
| 18 | -125593997262 |
| 19 | -4079362135854 |
| 20 | -32054212967294 |
| 21 | -33715330874838 |
| 22 | -600410923342450 |
| 23 | 9383532800084966 |
| 24 | 329821022627776798 |