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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | -5 |
| 5 | -10 |
| 6 | 16 |
| 7 | 154 |
| 8 | 365 |
| 9 | -750 |
| 10 | -9749 |
| 11 | -35222 |
| 12 | 20956 |
| 13 | 1013220 |
| 14 | 6007821 |
| 15 | 10272092 |
| 16 | -129948837 |
| 17 | -1405396426 |
| 18 | -6318145964 |
| 19 | 7407235766 |
| 20 | 371429230721 |
| 21 | 3172609248526 |
| 22 | 11070816858267 |
| 23 | -73488239926510 |
| 24 | -1500342260080360 |
| 25 | -11917913896465720 |
| 26 | -31231507292803479 |