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 | 1 |
| 2 | 3 |
| 3 | 1 |
| 4 | -3 |
| 5 | -1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | -5 |
| 10 | -1017 |
| 11 | 691 |
| 12 | 601 |
| 13 | -7 |
| 14 | -809 |
| 15 | 3617 |
| 16 | 922191 |
| 17 | -43867 |
| 18 | -6132631 |
| 19 | 174611 |
| 20 | 12988703 |
| 21 | -854513 |
| 22 | -1552922421 |
| 23 | 236364091 |
| 24 | 1139644561 |
| 25 | -8553103 |
| 26 | -7089687053 |
| 27 | 23749461029 |
| 28 | 378639019356093 |
| 29 | -8615841276005 |