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 | -5 |
| 3 | 61 |
| 4 | -917 |
| 5 | 15421 |
| 6 | -277733 |
| 7 | 5239117 |
| 8 | -102188021 |
| 9 | 2044131037 |
| 10 | -41706059525 |
| 11 | 864547613293 |
| 12 | -18157111255829 |
| 13 | 385517710342909 |
| 14 | -8261602828082213 |
| 15 | 178459989617336461 |
| 16 | -3881680470161846837 |