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) |
|---|---|
| 4 | 1 |
| 5 | 3 |
| 6 | 19 |
| 7 | 149 |
| 8 | 2581 |
| 9 | 84151 |
| 10 | 5201856 |
| 11 | 577050233 |
| 12 | 113372069299 |
| 13 | 39618015318982 |
| 14 | 24916462761069296 |
| 15 | 28563626972509456884 |
| 16 | 60366734349116636660402 |
| 17 | 237406975840304068884168139 |
| 18 | 1750330441810569047176394509086 |