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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 16 |
| 5 | 0 |
| 6 | 0 |
| 7 | 104 |
| 8 | 792 |
| 9 | 1120 |
| 10 | 6096 |
| 11 | 21344 |
| 12 | 114496 |
| 13 | 257728 |
| 14 | 1292544 |
| 15 | 3677568 |
| 16 | 17273760 |
| 17 | 46801984 |
| 18 | 211731376 |
| 19 | 611507360 |
| 20 | 2645699504 |
| 21 | 7725948608 |
| 22 | 32451640000 |
| 23 | 97488160384 |
| 24 | 397346625760 |
| 25 | 1214082434112 |
| 26 | 4835168968464 |
| 27 | 15039729265856 |
| 28 | 58641619298000 |