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 | 1 |
| 2 | 4 |
| 3 | 36 |
| 4 | 416 |
| 5 | 6000 |
| 6 | 106542 |
| 7 | 2242093 |
| 8 | 54399424 |
| 9 | 1495318752 |
| 10 | 45938780750 |
| 11 | 1559858659359 |
| 12 | 58007497143180 |
| 13 | 2344682328265823 |
| 14 | 102352889947823998 |
| 15 | 4798930456964580045 |
| 16 | 240518006611511552896 |
| 17 | 12832137350594892322464 |
| 18 | 726108032647676403262710 |
| 19 | 43434461707962856186584307 |