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 | 2 |
| 2 | -3 |
| 3 | -75 |
| 4 | -650 |
| 5 | -4507 |
| 6 | -28267 |
| 7 | -167406 |
| 8 | -955271 |
| 9 | -5310911 |
| 10 | -28962586 |
| 11 | -155616567 |
| 12 | -826329687 |
| 13 | -4345964510 |
| 14 | -22675946635 |
| 15 | -117526104883 |
| 16 | -605643805098 |
| 17 | -3105646720979 |
| 18 | -15856669574339 |
| 19 | -80653146223054 |