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 | 15 |
| 4 | 127 |
| 5 | 1743 |
| 6 | 36047 |
| 7 | 1051039 |
| 8 | 41082783 |
| 9 | 2073110239 |
| 10 | 131183712063 |
| 11 | 10171782421727 |
| 12 | 948427290027807 |
| 13 | 104693416370374783 |
| 14 | 13502772386271932927 |
| 15 | 2011983769934772172799 |
| 16 | 343000542276546601893439 |
| 17 | 66334607666382842941084991 |
| 18 | 14444628785932359077548728255 |
| 19 | 3518072269888902413311442552511 |