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) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 7 |
| 3 | 44 |
| 4 | 354 |
| 5 | 3328 |
| 6 | 35144 |
| 7 | 407984 |
| 8 | 5137824 |
| 9 | 69566144 |
| 10 | 1006372864 |
| 11 | 15481560064 |
| 12 | 252326173824 |
| 13 | 4344015683584 |
| 14 | 78793242566144 |
| 15 | 1502374856981504 |
| 16 | 30052439647908864 |
| 17 | 629485600310349824 |
| 18 | 13783057303819485184 |