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) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 24 |
| 3 | 176 |
| 4 | 1440 |
| 5 | 12608 |
| 6 | 115584 |
| 7 | 1095424 |
| 8 | 10646016 |
| 9 | 105522176 |
| 10 | 1062623232 |
| 11 | 10840977408 |
| 12 | 111811534848 |
| 13 | 1163909087232 |
| 14 | 12212421230592 |
| 15 | 129027376349184 |
| 16 | 1371482141884416 |
| 17 | 14656212306231296 |
| 18 | 157369985643577344 |
| 19 | 1696975718802522112 |
| 20 | 18369603773021552640 |