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 | 20 |
| 2 | -322 |
| 3 | -35320 |
| 4 | -8948 |
| 5 | 101825200 |
| 6 | 2068806280 |
| 7 | -399730640800 |
| 8 | -18450359755120 |
| 9 | 1939836986158400 |
| 10 | 158687177411937760 |
| 11 | -10831879491824892800 |
| 12 | -1476931152842107545920 |
| 13 | 64308780860328720300800 |
| 14 | 15148651417782595832021120 |
| 15 | -347060128580550788160064000 |