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 | 504 |
| 3 | 2136 |
| 4 | 18384 |
| 5 | 115656 |
| 6 | 785124 |
| 7 | 4998648 |
| 8 | 31834476 |
| 9 | 198736752 |
| 10 | 1231177296 |
| 11 | 7552688064 |
| 12 | 46020487500 |
| 13 | 278641166280 |
| 14 | 1678349335044 |
| 15 | 10062618187272 |
| 16 | 60089435895360 |
| 17 | 357550261665528 |
| 18 | 2120806295463156 |
| 19 | 12543856834626072 |