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 | 3 |
| 4 | 33 |
| 5 | 270 |
| 6 | 2025 |
| 7 | 14868 |
| 8 | 109851 |
| 9 | 827508 |
| 10 | 6397665 |
| 11 | 50932233 |
| 12 | 418175274 |
| 13 | 3542883864 |
| 14 | 30972408558 |
| 15 | 279287247333 |
| 16 | 2596195945977 |
| 17 | 24862074701208 |
| 18 | 245091667488207 |
| 19 | 2485294443056496 |
| 20 | 25903024863885465 |
| 21 | 277278282774462210 |