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) |
|---|---|
| 2 | 1 |
| 3 | 7 |
| 4 | 54 |
| 5 | 918 |
| 6 | 31072 |
| 7 | 2053184 |
| 8 | 266478640 |
| 9 | 68560228400 |
| 10 | 35159451505536 |
| 11 | 36021118923496320 |
| 12 | 73782296097354062336 |
| 13 | 302225812400352055040512 |
| 14 | 2475866621867539032536216576 |
| 15 | 40564755669895936890639118713856 |
| 16 | 1329227401230786888692092742930946048 |