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 | 2 |
| 4 | 4 |
| 5 | 10 |
| 6 | 20 |
| 7 | 68 |
| 8 | 154 |
| 9 | 644 |
| 10 | 2210 |
| 11 | 6578 |
| 12 | 35308 |
| 13 | 92378 |
| 14 | 310154 |
| 15 | 1042404 |
| 16 | 5617820 |
| 17 | 35515634 |
| 18 | 184055430 |
| 19 | 1082950218 |
| 20 | 5386096364 |
| 21 | 19304763268 |
| 22 | 254772473240 |
| 23 | 1383442606194 |