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 | 13 |
| 4 | 97 |
| 5 | 741 |
| 6 | 7291 |
| 7 | 81313 |
| 8 | 1027713 |
| 9 | 14231017 |
| 10 | 220911571 |
| 11 | 3730744821 |
| 12 | 68096325793 |
| 13 | 1339705629133 |
| 14 | 28225576881867 |
| 15 | 634123159354441 |
| 16 | 15127595174135041 |
| 17 | 381586517104288593 |
| 18 | 10147599723510322723 |
| 19 | 283846981316172613597 |
| 20 | 8324822922497497733601 |