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) |
|---|---|
| 3 | 0 |
| 4 | 3 |
| 5 | 19 |
| 6 | 119 |
| 7 | 839 |
| 8 | 6719 |
| 9 | 60479 |
| 10 | 604799 |
| 11 | 6652799 |
| 12 | 79833599 |
| 13 | 1037836799 |
| 14 | 14529715199 |
| 15 | 217945727999 |
| 16 | 3487131647999 |
| 17 | 59281238015999 |
| 18 | 1067062284287999 |
| 19 | 20274183401471999 |
| 20 | 405483668029439999 |