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 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 61 |
| 6 | 361 |
| 7 | 1261 |
| 8 | 3361 |
| 9 | -37799 |
| 10 | 15121 |
| 11 | 2522521 |
| 12 | 20005921 |
| 13 | 486563221 |
| 14 | 363363001 |
| 15 | -12486293819 |
| 16 | 3113772481 |
| 17 | -12960051533519 |
| 18 | 8909829442081 |
| 19 | 528011239172401 |
| 20 | 241435513794241 |
| 21 | 1381310884267333741 |
| 22 | 3097715443570441 |
| 23 | -49080307628073705059 |