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 | 0 |
| 1 | -1 |
| 2 | 3 |
| 3 | -1 |
| 4 | -77 |
| 5 | -13921 |
| 6 | 791043 |
| 7 | 23892959 |
| 8 | -3518362637 |
| 9 | -801110007361 |
| 10 | 149920222346883 |
| 11 | 24069808471917119 |
| 12 | -7334638751184472397 |
| 13 | -2673575321959933341601 |
| 14 | 1059696929013386749787523 |
| 15 | 413637485668406346391368479 |