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 | 32 |
| 3 | 870 |
| 4 | 46224 |
| 5 | 4037880 |
| 6 | 522956160 |
| 7 | 93928267440 |
| 8 | 22324392518400 |
| 9 | 6780385526302080 |
| 10 | 2561327494111411200 |
| 11 | 1177652997443424902400 |
| 12 | 647478071469567800985600 |
| 13 | 419450149241406188889984000 |
| 14 | 316196664211373618844934963200 |
| 15 | 274410818470142134209609852672000 |