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 | 1 |
| 1 | 9 |
| 2 | 50 |
| 3 | 294 |
| 4 | 1944 |
| 5 | 14520 |
| 6 | 121680 |
| 7 | 1134000 |
| 8 | 11652480 |
| 9 | 130999680 |
| 10 | 1600300800 |
| 11 | 21115987200 |
| 12 | 299376000000 |
| 13 | 4539498163200 |
| 14 | 73316942899200 |
| 15 | 1256675067648000 |
| 16 | 22784918188032000 |
| 17 | 435717099417600000 |