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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 13 |
| 5 | 55 |
| 6 | 256 |
| 7 | 1274 |
| 8 | 6791 |
| 9 | 38553 |
| 10 | 232171 |
| 11 | 1477355 |
| 12 | 9898780 |
| 13 | 69621864 |
| 14 | 512585529 |
| 15 | 3940556611 |
| 16 | 31560327945 |
| 17 | 262805569159 |
| 18 | 2271094695388 |
| 19 | 20333574916690 |
| 20 | 188322882941471 |
| 21 | 1801737999086129 |
| 22 | 17783472151154007 |
| 23 | 180866601699482803 |
| 24 | 1893373126840572056 |