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 | 3 |
| 2 | 42 |
| 3 | 990 |
| 4 | 32760 |
| 5 | 1395360 |
| 6 | 72681840 |
| 7 | 4475671200 |
| 8 | 318073392000 |
| 9 | 25622035084800 |
| 10 | 2306992893004800 |
| 11 | 229601607198163200 |
| 12 | 25028504609870361600 |
| 13 | 2965681982933429760000 |
| 14 | 379534960108578193920000 |
| 15 | 52170410224819317150720000 |
| 16 | 7666009844358186506465280000 |
| 17 | 1199151678674216896627654656000 |