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) |
|---|---|
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 4 |
| 10 | 5 |
| 11 | 14 |
| 12 | 28 |
| 13 | 86 |
| 14 | 211 |
| 15 | 648 |
| 16 | 1878 |
| 17 | 5931 |
| 18 | 18326 |
| 19 | 58746 |
| 20 | 187620 |
| 21 | 608065 |
| 22 | 1975191 |
| 23 | 6461809 |
| 24 | 21212414 |