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 | 15 |
| 2 | 151 |
| 3 | 1275 |
| 4 | 9751 |
| 5 | 70035 |
| 6 | 481951 |
| 7 | 3216795 |
| 8 | 20991751 |
| 9 | 134667555 |
| 10 | 852639151 |
| 11 | 5343198315 |
| 12 | 33212784151 |
| 13 | 205111785075 |
| 14 | 1260114546751 |
| 15 | 7708980203835 |
| 16 | 46999640806951 |
| 17 | 285743822630595 |
| 18 | 1733261544204751 |