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 | -1 |
| 3 | 3 |
| 4 | -44 |
| 5 | 49 |
| 6 | -9895 |
| 7 | 3124 |
| 8 | -54429 |
| 9 | 2624879 |
| 10 | -59124785 |
| 11 | 163841201 |
| 12 | -2508904105349 |
| 13 | 1776678914237 |
| 14 | -2029995134495 |
| 15 | 175211074573961 |
| 16 | -21557683580436716 |
| 17 | 94127808754677868 |
| 18 | -87882971047931164843 |
| 19 | 161354083950193175137 |
| 20 | -104683178840085862057001 |