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 | 1 |
| 2 | 0 |
| 3 | -5 |
| 4 | -10 |
| 5 | 40 |
| 6 | 245 |
| 7 | -26 |
| 8 | -4375 |
| 9 | -11410 |
| 10 | 53040 |
| 11 | 377850 |
| 12 | -12320 |
| 13 | -7988194 |
| 14 | -23011625 |
| 15 | 106662595 |
| 16 | 824671575 |
| 17 | 64095550 |
| 18 | -18490968680 |
| 19 | -57052839001 |
| 20 | 254513058375 |
| 21 | 2098532784575 |
| 22 | 419490572800 |
| 23 | -48205987947600 |
| 24 | -157458581103395 |
| 25 | 666628546612606 |
| 26 | 5824573247731250 |