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 | 69 |
| 4 | 2505 |
| 5 | 10077 |
| 6 | -716415 |
| 7 | -14740491 |
| 8 | 213018105 |
| 9 | 15676762317 |
| 10 | 98170027185 |
| 11 | -17112616737051 |
| 12 | -553855541534295 |
| 13 | 15477991707447357 |
| 14 | 1557738998240770785 |
| 15 | 10238839745149426389 |
| 16 | -3849999044450765494695 |