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 | 30 |
| 3 | 153 |
| 4 | 412 |
| 5 | 1065 |
| 6 | 1386 |
| 7 | 7105 |
| 8 | -24072 |
| 9 | 275697 |
| 10 | -2656970 |
| 11 | 29387721 |
| 12 | -352403820 |
| 13 | 4581620953 |
| 14 | -64142155518 |
| 15 | 962133092145 |
| 16 | -15394128425744 |
| 17 | 261700184657505 |
| 18 | -4710603321945522 |
| 19 | 89501463119441017 |
| 20 | -1790029262385620340 |
| 21 | 37590614510102111241 |