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 | -64 |
| 3 | -665 |
| 4 | -1351 |
| 5 | 33111 |
| 6 | 408149 |
| 7 | 1959491 |
| 8 | -4502590 |
| 9 | -149420286 |
| 10 | -1182474566 |
| 11 | -3678670450 |
| 12 | 22384197409 |
| 13 | 377982157035 |
| 14 | 2474860645111 |
| 15 | 6161653683590 |
| 16 | -48899064011245 |
| 17 | -695916857379611 |
| 18 | -4275491639488601 |
| 19 | -10750056317745704 |
| 20 | 69316545348329853 |