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 | 4 |
| 2 | 48 |
| 3 | 9 |
| 4 | 640 |
| 5 | 390 |
| 6 | 20 |
| 7 | 8960 |
| 8 | 20160 |
| 9 | 3192 |
| 10 | 60 |
| 11 | 129024 |
| 12 | 1106424 |
| 13 | 652784 |
| 14 | 48720 |
| 15 | 45 |
| 16 | 1892352 |
| 17 | 62606544 |
| 18 | 134432480 |
| 19 | 41801760 |
| 20 | 26010 |
| 21 | 420 |
| 22 | 28114944 |
| 23 | 3611217792 |
| 24 | 28244153600 |
| 25 | 36951200000 |
| 26 | 21594300 |
| 27 | 8168160 |
| 28 | 102 |
| 29 | 421724160 |
| 30 | 211096262400 |