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 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 22 |
| 5 | 154 |
| 6 | 931 |
| 7 | 14160 |
| 8 | 195952 |
| 9 | 2808960 |
| 10 | 58924800 |
| 11 | 1585406976 |
| 12 | 38032879616 |
| 13 | 1491624640512 |
| 14 | 52205681184768 |
| 15 | 2118556421369856 |