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 | 0 |
| 3 | 4 |
| 4 | 16 |
| 5 | 48 |
| 6 | 128 |
| 7 | 512 |
| 8 | 2304 |
| 9 | 6912 |
| 10 | 22528 |
| 11 | 273408 |
| 12 | 2097152 |
| 13 | 14929920 |
| 14 | 50331648 |
| 15 | 390905856 |
| 16 | 1644167168 |
| 17 | 12279939072 |
| 18 | 69660573696 |
| 19 | 865782202368 |
| 20 | 5566277615616 |
| 21 | 41248865910784 |
| 22 | 215055782117376 |
| 23 | 2385859554836480 |
| 24 | 25783171861708800 |
| 25 | 146322302697472000 |
| 26 | 1107244165160239104 |
| 27 | 11063259546716733440 |
| 28 | 76787161889935196160 |