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 | -9 |
| 2 | 97 |
| 3 | -36 |
| 4 | -481 |
| 5 | 300 |
| 6 | 10471 |
| 7 | -17004 |
| 8 | -3572161 |
| 9 | 1503900 |
| 10 | 879402485 |
| 11 | -204957852 |
| 12 | -851608333333 |
| 13 | 39666688620 |
| 14 | 2959809513079 |
| 15 | -10337889346380 |
| 16 | -74944106556170657 |
| 17 | 3489994294713660 |
| 18 | 6362557475056509757 |
| 19 | -1481439997178305788 |
| 20 | -8686827386554851273011 |