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 | 24 |
| 5 | 600 |
| 6 | 5400 |
| 7 | 29400 |
| 8 | 117600 |
| 9 | 381024 |
| 10 | 1058400 |
| 11 | 2613600 |
| 12 | 5880600 |
| 13 | 12269400 |
| 14 | 24048024 |
| 15 | 44717400 |
| 16 | 79497600 |
| 17 | 135945600 |
| 18 | 224726400 |
| 19 | 360561024 |
| 20 | 563376600 |
| 21 | 859685400 |
| 22 | 1284221400 |
| 23 | 1881864600 |
| 24 | 2709885024 |
| 25 | 3840540000 |
| 26 | 5364060000 |