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) |
|---|---|
| 2 | 0 |
| 3 | 11 |
| 4 | 46 |
| 5 | 274 |
| 6 | 1956 |
| 7 | 16008 |
| 8 | 147120 |
| 9 | 1498320 |
| 10 | 16742880 |
| 11 | 203656320 |
| 12 | 2678780160 |
| 13 | 37888300800 |
| 14 | 573444748800 |
| 15 | 9248083891200 |
| 16 | 158328230860800 |
| 17 | 2867904245606400 |
| 18 | 54799402065408000 |
| 19 | 1101605810393088000 |
| 20 | 23241327926648832000 |
| 21 | 513476773573091328000 |
| 22 | 11855774776045584384000 |