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 | 2 |
| 2 | 3 |
| 3 | 4 |
| 4 | 9 |
| 5 | 28 |
| 6 | 117 |
| 7 | 1063 |
| 8 | 59305 |
| 9 | 20813950 |
| 10 | 297984461349 |
| 11 | 1369656755010903367 |
| 12 | 44484668455038959221955630581 |
| 13 | 2160062633529958340011598192248388618489251093 |