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 | 5 |
| 3 | -11 |
| 4 | 83 |
| 5 | -143 |
| 6 | 625 |
| 7 | -1843 |
| 8 | 24323 |
| 9 | 61477 |
| 10 | -14165 |
| 11 | -8084893 |
| 12 | 31181719 |
| 13 | 1682401061 |
| 14 | -3166220215 |
| 15 | -251783137859 |
| 16 | 3865962456803 |
| 17 | 394670372519917 |
| 18 | -765052915887545 |
| 19 | -98394908192751193 |
| 20 | 384080734825119709 |
| 21 | 60838795345430052431 |
| 22 | -119312155199695296505 |
| 23 | -22845758944383820991909 |