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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 40320 |
| 9 | 40311 |
| 10 | 40230 |
| 11 | 39330 |
| 12 | 28440 |
| 13 | -114120 |
| 14 | -2121840 |
| 15 | -32392080 |
| 16 | -518878080 |
| 17 | -518878063 |
| 18 | -518877774 |
| 19 | -518872266 |
| 20 | -518761800 |
| 21 | -516436200 |
| 22 | -465156720 |
| 23 | 716713200 |
| 24 | 29135312640 |
| 25 | 29135312615 |
| 26 | 29135311990 |
| 27 | 29135295090 |
| 28 | 29134821240 |