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 | 2 |
| 2 | 16 |
| 3 | 108 |
| 4 | 640 |
| 5 | 5600 |
| 6 | 36288 |
| 7 | 264992 |
| 8 | 1536000 |
| 9 | 12387168 |
| 10 | 85120000 |
| 11 | 658519752 |
| 12 | 3135283200 |
| 13 | 32296336800 |
| 14 | 216063877120 |
| 15 | 1450340640000 |
| 16 | 8333819904000 |
| 17 | 77537969371008 |
| 18 | 488237947481088 |
| 19 | 3790563394976072 |
| 20 | 19162214400000000 |
| 21 | 170264753751665664 |
| 22 | 1245495178700551680 |