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 | -2 |
| 3 | 23 |
| 4 | -276 |
| 5 | 4509 |
| 6 | -91190 |
| 7 | 2205587 |
| 8 | -62104168 |
| 9 | 1995807993 |
| 10 | -72089029802 |
| 11 | 2891304481999 |
| 12 | -127498010037244 |
| 13 | 6131189086886421 |
| 14 | -319320539953144158 |
| 15 | 17905976286288568267 |
| 16 | -1075611833288214177232 |
| 17 | 68909527979479961534705 |