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 | 4 |
| 1 | 13 |
| 2 | 49 |
| 3 | 193 |
| 4 | 769 |
| 5 | 3073 |
| 6 | 12289 |
| 7 | 49153 |
| 8 | 196609 |
| 9 | 786433 |
| 10 | 3145729 |
| 11 | 12582913 |
| 12 | 50331649 |
| 13 | 201326593 |
| 14 | 805306369 |
| 15 | 3221225473 |
| 16 | 12884901889 |
| 17 | 51539607553 |
| 18 | 206158430209 |
| 19 | 824633720833 |
| 20 | 3298534883329 |
| 21 | 13194139533313 |
| 22 | 52776558133249 |