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 | -15 |
| 2 | 313 |
| 3 | -330 |
| 4 | 55679 |
| 5 | -9130 |
| 6 | 243319 |
| 7 | -191510 |
| 8 | 32684159 |
| 9 | -4958514 |
| 10 | -59283835 |
| 11 | 32834450 |
| 12 | 1367918488907 |
| 13 | -23531909258 |
| 14 | -4237502707769 |
| 15 | 5708376915450 |
| 16 | 108358154365632223 |
| 17 | -1937266788836962 |
| 18 | -9193903453338647027 |
| 19 | 822123254132465890 |
| 20 | 12552837966477699775789 |