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 | 4 |
| 2 | 3 |
| 3 | 204 |
| 4 | 280 |
| 5 | 2280 |
| 6 | 12596 |
| 7 | 12797 |
| 8 | 831996 |
| 9 | 1149440 |
| 10 | 9341440 |
| 11 | 51622404 |
| 12 | 52441603 |
| 13 | 3409523404 |
| 14 | 4710402840 |
| 15 | 38281220840 |
| 16 | 211548594996 |
| 17 | 214905676797 |
| 18 | 13972226073596 |
| 19 | 19303229690880 |
| 20 | 156876433658880 |
| 21 | 866926090675204 |
| 22 | 880683411072003 |