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 | 6 |
| 3 | 60 |
| 4 | 770 |
| 5 | 11466 |
| 6 | 188496 |
| 7 | 3325608 |
| 8 | 61866090 |
| 9 | 1199333850 |
| 10 | 24030289140 |
| 11 | 494663027040 |
| 12 | 10414559269296 |
| 13 | 223487031938800 |
| 14 | 4874879691748800 |
| 15 | 107852781825352080 |
| 16 | 2415945569351185530 |
| 17 | 54714061423541554650 |
| 18 | 1251237165698155135500 |
| 19 | 28864572348777684057000 |