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 | -8 |
| 2 | 37 |
| 3 | -144 |
| 4 | 540 |
| 5 | -2016 |
| 6 | 7524 |
| 7 | -28080 |
| 8 | 104796 |
| 9 | -391104 |
| 10 | 1459620 |
| 11 | -5447376 |
| 12 | 20329884 |
| 13 | -75872160 |
| 14 | 283158756 |
| 15 | -1056762864 |
| 16 | 3943892700 |
| 17 | -14718807936 |
| 18 | 54931339044 |
| 19 | -205006548240 |
| 20 | 765094853916 |
| 21 | -2855372867424 |
| 22 | 10656396615780 |
| 23 | -39770213595696 |
| 24 | 148424457767004 |