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 | 8 |
| 5 | 48 |
| 6 | 368 |
| 7 | 3408 |
| 8 | 36848 |
| 9 | 454608 |
| 10 | 6294128 |
| 11 | 96556368 |
| 12 | 1624775408 |
| 13 | 29744591568 |
| 14 | 588384837488 |
| 15 | 12503968334928 |
| 16 | 284065406275568 |
| 17 | 6869235761650128 |
| 18 | 176150548586638448 |
| 19 | 4774198652678411088 |