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 | 4 |
| 5 | 30 |
| 6 | 284 |
| 7 | 3217 |
| 8 | 42100 |
| 9 | 621936 |
| 10 | 10206956 |
| 11 | 183946656 |
| 12 | 3608229588 |
| 13 | 76499111202 |
| 14 | 1742909621024 |
| 15 | 42465280193704 |
| 16 | 1101811478508828 |
| 17 | 30331386700718440 |
| 18 | 883010853509597608 |
| 19 | 27105284242369828508 |
| 20 | 874996700615422755068 |