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) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 27 |
| 4 | 539 |
| 5 | 9850 |
| 6 | 176554 |
| 7 | 3197348 |
| 8 | 59354028 |
| 9 | 1137868848 |
| 10 | 22614500016 |
| 11 | 466814750688 |
| 12 | 10015620672672 |
| 13 | 223359393479040 |
| 14 | 5175622796192640 |
| 15 | 124533006364442880 |
| 16 | 3109120944743427840 |
| 17 | 80473740053567016960 |