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 | 2 |
| 2 | -247 |
| 3 | -6534 |
| 4 | -65455 |
| 5 | -390382 |
| 6 | -1678887 |
| 7 | -5762614 |
| 8 | -16770655 |
| 9 | -43027038 |
| 10 | -99940951 |
| 11 | -214181734 |
| 12 | -429450255 |
| 13 | -814136398 |
| 14 | -1471006087 |
| 15 | -2548541718 |
| 16 | -4251920575 |
| 17 | -6846617278 |
| 18 | -10632540087 |
| 19 | -15821301574 |
| 20 | -22113215599 |