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 | 180 |
| 2 | -3780 |
| 3 | 447840 |
| 4 | -59046660 |
| 5 | 8921092680 |
| 6 | -1463828444640 |
| 7 | 253953515257920 |
| 8 | -45858209756343300 |
| 9 | 8534765953624978260 |
| 10 | -1626301691950399586280 |
| 11 | 315807346469727624396960 |
| 12 | -62284193156782292089690080 |
| 13 | 12443904711281870749228431240 |