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) |
|---|---|
| 1 | 1 |
| 2 | -3 |
| 3 | 7 |
| 4 | -5 |
| 5 | -83 |
| 6 | 637 |
| 7 | -1425 |
| 8 | -22341 |
| 9 | 318149 |
| 10 | -1415491 |
| 11 | -18988393 |
| 12 | 444896699 |
| 13 | -3268880739 |
| 14 | -35114352579 |
| 15 | 1317630731647 |
| 16 | -14445395761157 |
| 17 | -112227733823435 |
| 18 | 7047241310852605 |
| 19 | -108366459009937881 |
| 20 | -487554173851570053 |
| 21 | 61301180146129065101 |
| 22 | -1271086841777475748099 |
| 23 | -1158631507880606959729 |