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 | 5 |
| 2 | 41 |
| 3 | 420 |
| 4 | 4986 |
| 5 | 66810 |
| 6 | 1002088 |
| 7 | 16806508 |
| 8 | 315407579 |
| 9 | 6620028959 |
| 10 | 154924624070 |
| 11 | 4020925173996 |
| 12 | 114962504927760 |
| 13 | 3595318334723744 |
| 14 | 122162584874240256 |
| 15 | 4482358458470131580 |
| 16 | 176643906831439963801 |
| 17 | 7441446644628587378829 |
| 18 | 333713924433617162053239 |
| 19 | 15872723846851837735096664 |