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 | 3 |
| 3 | 15 |
| 4 | 100 |
| 5 | 801 |
| 6 | 7296 |
| 7 | 73174 |
| 8 | 791751 |
| 9 | 9116613 |
| 10 | 110640310 |
| 11 | 1405349658 |
| 12 | 18585016509 |
| 13 | 254855278565 |
| 14 | 3612425924919 |
| 15 | 52793266545585 |
| 16 | 793851646358364 |
| 17 | 12261570084250926 |
| 18 | 194260753173421656 |
| 19 | 3153098224666860712 |