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) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 28 |
| 4 | 90 |
| 5 | 1488 |
| 6 | 945 |
| 7 | 182880 |
| 8 | 9450 |
| 9 | 8241408 |
| 10 | 93555 |
| 11 | 14856307200 |
| 12 | 638512875 |
| 13 | 1569400842240 |
| 14 | 18243225 |
| 15 | 5713142135500800 |
| 16 | 325641566250 |
| 17 | 1096948397364019200 |
| 18 | 38979295480125 |
| 19 | 6713362606110031872000 |
| 20 | 1531329465290625 |
| 21 | 408173030347971900211200 |
| 22 | 13447856940643125 |