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 | 1 |
| 4 | 12 |
| 5 | 130 |
| 6 | 1485 |
| 7 | 18508 |
| 8 | 253400 |
| 9 | 3805723 |
| 10 | 62437500 |
| 11 | 1113510409 |
| 12 | 21479997957 |
| 13 | 446094038806 |
| 14 | 9930796412082 |
| 15 | 236037249893092 |
| 16 | 5968192832899412 |
| 17 | 160007282538148508 |
| 18 | 4534905316824903144 |
| 19 | 135500246340709682692 |
| 20 | 4257646241716404353684 |
| 21 | 140366073694357927723936 |
| 22 | 4845119946789226304526392 |