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 | -7 |
| 3 | -31 |
| 4 | -23 |
| 5 | 2239 |
| 6 | 39889 |
| 7 | 603521 |
| 8 | -27466831 |
| 9 | -2445382081 |
| 10 | -204734091383 |
| 11 | 7545563759329 |
| 12 | 7265319037194073 |
| 13 | 2502938339020429439 |
| 14 | 404477135616551491361 |
| 15 | -932929530161758614571519 |