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 | 0 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 12 |
| 9 | 21 |
| 10 | 74 |
| 11 | 309 |
| 12 | 1376 |
| 13 | 5016 |
| 14 | 27198 |
| 15 | 138592 |
| 16 | 928544 |
| 17 | 4735266 |
| 18 | 31263708 |
| 19 | 206761952 |
| 20 | 1677199872 |
| 21 | 11111483094 |