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) |
|---|---|
| 1 | 0 |
| 2 | -1 |
| 3 | 2 |
| 4 | -4 |
| 5 | 6 |
| 6 | -5 |
| 7 | -84 |
| 8 | 245 |
| 9 | 924 |
| 10 | -8816 |
| 11 | -78556 |
| 12 | -58667 |
| 13 | 6779732 |
| 14 | 10484275 |
| 15 | -363899598 |
| 16 | -6434306752 |
| 17 | -13046891490 |
| 18 | 20608641823 |
| 19 | 1894093427008 |
| 20 | -6177545952015 |
| 21 | 18227184915788 |
| 22 | -46023445768832 |
| 23 | -8765268354146700 |
| 24 | -1210879926442292743 |
| 25 | -149657142827643535248 |