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 | 1 |
| 3 | 2 |
| 4 | -3 |
| 5 | 32 |
| 6 | -339 |
| 7 | 4424 |
| 8 | -75189 |
| 9 | 1428614 |
| 10 | -32858093 |
| 11 | 952884728 |
| 12 | -29539426531 |
| 13 | 1092958781688 |
| 14 | -44811310049165 |
| 15 | 1926886332114142 |
| 16 | -90563657609364621 |
| 17 | 4799873853296324972 |
| 18 | -283192557344483173287 |
| 19 | 17274745998013473570574 |
| 20 | -1157407981866902729228387 |