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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 20 |
| 4 | 217 |
| 5 | 3206 |
| 6 | 59000 |
| 7 | 1288184 |
| 8 | 32391811 |
| 9 | 919625298 |
| 10 | 29062669744 |
| 11 | 1011423361344 |
| 12 | 38432306102230 |
| 13 | 1583371370586372 |
| 14 | 70311532983998416 |
| 15 | 3348279599587251984 |
| 16 | 170232740676793931347 |
| 17 | 9204327574128495048866 |