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 | -13 |
| 2 | 195 |
| 3 | -3315 |
| 4 | 62673 |
| 5 | -1299285 |
| 6 | 29228355 |
| 7 | -707636475 |
| 8 | 18316505025 |
| 9 | -504116658045 |
| 10 | 14685387955875 |
| 11 | -451033728019875 |
| 12 | 14555826008348625 |
| 13 | -492141539705941125 |
| 14 | 17387673626552904675 |
| 15 | -640456882350467056875 |