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 | 192 |
| 5 | 2560 |
| 6 | 19200 |
| 7 | 107520 |
| 8 | 501760 |
| 9 | 2064384 |
| 10 | 7741440 |
| 11 | 27033600 |
| 12 | 89210880 |
| 13 | 281149440 |
| 14 | 852819968 |
| 15 | 2504785920 |
| 16 | 7156531200 |
| 17 | 19964887040 |
| 18 | 54546923520 |
| 19 | 146314100736 |
| 20 | 386106654720 |
| 21 | 1004116377600 |
| 22 | 2577232035840 |
| 23 | 6536738897920 |
| 24 | 16401272143872 |
| 25 | 40748502220800 |