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 | 3 |
| 2 | -15 |
| 3 | 113 |
| 4 | -5397 |
| 5 | 84813 |
| 6 | -3267755 |
| 7 | 74391561 |
| 8 | -15633072909 |
| 9 | 465681118929 |
| 10 | -31041303829713 |
| 11 | 1145088996404679 |
| 12 | -185348722911971841 |
| 13 | 8165727090278785521 |
| 14 | -778296382754673737187 |
| 15 | 39898888480559205453945 |
| 16 | -35033447016186321707305533 |