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 | -4 |
| 3 | 25 |
| 4 | -194 |
| 5 | 1603 |
| 6 | -15264 |
| 7 | 122316 |
| 8 | -1897710 |
| 9 | -8845133 |
| 10 | -1169435932 |
| 11 | -52853978047 |
| 12 | -3193246498792 |
| 13 | -205347570309000 |
| 14 | -14534295599537024 |
| 15 | -1115833257773950536 |
| 16 | -92445637289048967654 |
| 17 | -8219735646409095418617 |