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 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 3 |
| 6 | 12 |
| 7 | 49 |
| 8 | 460 |
| 9 | 4994 |
| 10 | 68234 |
| 11 | 997486 |
| 12 | 15582567 |
| 13 | 253005521 |
| 14 | 4250680376 |
| 15 | 73293572869 |
| 16 | 1293638724177 |