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 | 24 |
| 4 | 192 |
| 5 | 1032 |
| 6 | 5376 |
| 7 | 26688 |
| 8 | 128880 |
| 9 | 605664 |
| 10 | 2802576 |
| 11 | 12755136 |
| 12 | 57525552 |
| 13 | 256574352 |
| 14 | 1137418464 |
| 15 | 5001796944 |
| 16 | 21899428128 |
| 17 | 95296531680 |
| 18 | 413331190896 |