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 | 24 |
| 4 | 233 |
| 5 | 2860 |
| 6 | 42875 |
| 7 | 758856 |
| 8 | 15488657 |
| 9 | 358164432 |
| 10 | 9254769459 |
| 11 | 264273873600 |
| 12 | 8264362186489 |
| 13 | 280896392748608 |
| 14 | 10310601442639147 |
| 15 | 406479520869636480 |
| 16 | 17129450693008029729 |
| 17 | 768404013933189112064 |
| 18 | 36557893891263190204259 |
| 19 | 1838650651518153170939904 |