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 | 0 |
| 3 | 90 |
| 4 | -1890 |
| 5 | 36540 |
| 6 | -729540 |
| 7 | 15507450 |
| 8 | -353908170 |
| 9 | 8680615020 |
| 10 | -228436914420 |
| 11 | 6431738433120 |
| 12 | -193144902350400 |
| 13 | 6166945337372820 |
| 14 | -208728050864680620 |
| 15 | 7467661073819689470 |
| 16 | -281666767117960443870 |
| 17 | 11173071188540083124700 |