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 | 0 |
| 3 | 3 |
| 4 | -5 |
| 5 | -17 |
| 6 | 103 |
| 7 | 57 |
| 8 | -2707 |
| 9 | 6785 |
| 10 | 84135 |
| 11 | -659369 |
| 12 | -2129683 |
| 13 | 55537445 |
| 14 | -103722105 |
| 15 | -4630217025 |
| 16 | 37357780827 |
| 17 | 334163569535 |
| 18 | -7214177094045 |
| 19 | -2126819153101 |
| 20 | 1233139349668817 |
| 21 | -8794491537166765 |
| 22 | -184459444459530193 |
| 23 | 3483053621920936363 |
| 24 | 15570880115951580635 |