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 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 5 |
| 6 | 14 |
| 7 | 50 |
| 8 | 233 |
| 9 | 1248 |
| 10 | 7593 |
| 11 | 49536 |
| 12 | 339483 |
| 13 | 2404472 |
| 14 | 17468202 |
| 15 | 129459090 |
| 16 | 975647292 |
| 17 | 7458907217 |
| 18 | 57744122366 |
| 19 | 452028275567 |
| 20 | 3573870490382 |