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 | 3 |
| 2 | 9 |
| 3 | 24 |
| 4 | 45 |
| 5 | -24 |
| 6 | -747 |
| 7 | -3864 |
| 8 | -7623 |
| 9 | 48576 |
| 10 | 548001 |
| 11 | 2175360 |
| 12 | -5269275 |
| 13 | -133496448 |
| 14 | -785549331 |
| 15 | 789324288 |
| 16 | 52523738865 |
| 17 | 398157422592 |
| 18 | -157735851975 |
| 19 | -31426593116160 |
| 20 | -278010988509411 |
| 21 | 108354846277632 |
| 22 | 27060485795905221 |
| 23 | 257882404940021760 |