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) |
|---|---|
| 2 | 4 |
| 3 | 28 |
| 4 | 16 |
| 5 | 176 |
| 6 | 4950 |
| 7 | 8910 |
| 8 | 1408 |
| 9 | 346500 |
| 10 | 277992 |
| 11 | 7542080 |
| 12 | 326656 |
| 13 | 544320 |
| 14 | 120400000 |
| 15 | 145213440 |
| 16 | 48549888 |
| 17 | 4733575168 |
| 18 | 536813568 |
| 19 | 2149576704 |
| 20 | 3057500160 |
| 21 | 938539560960 |
| 22 | 1358951178240 |
| 23 | 36324805836800 |
| 24 | 99956555776 |
| 25 | 49212503949312 |
| 26 | 118747221196800 |
| 27 | 59461613912064 |
| 28 | 13749193801728 |