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) |
|---|---|
| 3 | 9 |
| 4 | 120 |
| 5 | 952 |
| 6 | 5664 |
| 7 | 27888 |
| 8 | 120064 |
| 9 | 467712 |
| 10 | 1686528 |
| 11 | 5719296 |
| 12 | 18450432 |
| 13 | 57108480 |
| 14 | 170713088 |
| 15 | 495366144 |
| 16 | 1401028608 |
| 17 | 3874881536 |
| 18 | 10508304384 |
| 19 | 28005433344 |
| 20 | 73485778944 |
| 21 | 190154539008 |
| 22 | 485895438336 |
| 23 | 1227495571456 |