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 | 3 |
| 4 | 7 |
| 5 | -25 |
| 6 | -31 |
| 7 | 427 |
| 8 | 127 |
| 9 | -12465 |
| 10 | -2555 |
| 11 | 555731 |
| 12 | 1414477 |
| 13 | -35135945 |
| 14 | -57337 |
| 15 | 2990414715 |
| 16 | 118518239 |
| 17 | -329655706465 |
| 18 | -5749691557 |
| 19 | 45692713833379 |
| 20 | 91546277357 |
| 21 | -7777794952988025 |
| 22 | -1792042792463 |
| 23 | 1595024111042171723 |
| 24 | 1982765468311237 |
| 25 | -387863354088927172625 |