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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | -5 |
| 4 | -8 |
| 5 | 61 |
| 6 | 130 |
| 7 | -1385 |
| 8 | -3680 |
| 9 | 50521 |
| 10 | 160816 |
| 11 | -2702765 |
| 12 | -10026368 |
| 13 | 199360981 |
| 14 | 844583440 |
| 15 | -19391512145 |
| 16 | -92369507840 |
| 17 | 2404879675441 |
| 18 | 12722897618176 |
| 19 | -370371188237525 |
| 20 | -2154662195222528 |
| 21 | 69348874393137901 |
| 22 | 440001333689382400 |
| 23 | -15514534163557086905 |
| 24 | -106615331831035289600 |
| 25 | 4087072509293123892361 |