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 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | -8 |
| 5 | -56 |
| 6 | -112 |
| 7 | 848 |
| 8 | 9088 |
| 9 | 25216 |
| 10 | -310528 |
| 11 | -4334848 |
| 12 | -14701568 |
| 13 | 270029824 |
| 14 | 4554426368 |
| 15 | 17536821248 |
| 16 | -458243735552 |
| 17 | -8926669144064 |
| 18 | -37024075153408 |
| 19 | 1341521605885952 |
| 20 | 29290212127670272 |
| 21 | 125297096967061504 |
| 22 | -6224109737622372352 |