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 | 0 |
| 2 | 0 |
| 3 | 9 |
| 4 | 306 |
| 5 | 4361 |
| 6 | 34059 |
| 7 | 185181 |
| 8 | 777280 |
| 9 | 2710074 |
| 10 | 8181558 |
| 11 | 22067973 |
| 12 | 54285858 |
| 13 | 123791067 |
| 14 | 264749849 |
| 15 | 536146569 |
| 16 | 1035584592 |
| 17 | 1919530804 |
| 18 | 3430908108 |
| 19 | 5937810417 |
| 20 | 9984193986 |
| 21 | 16358592141 |
| 22 | 26181281511 |
| 23 | 41019234245 |
| 24 | 63028246512 |
| 25 | 95136210222 |
| 26 | 141264963970 |
| 27 | 206611069197 |