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 | 3 |
| 2 | 7 |
| 3 | 29 |
| 4 | 65 |
| 5 | 69 |
| 6 | 81 |
| 7 | 257 |
| 8 | 259 |
| 9 | 4097 |
| 10 | 4113 |
| 11 | 4129 |
| 12 | 262145 |
| 13 | 262149 |
| 14 | 1048577 |
| 15 | 1048583 |
| 16 | 16777217 |
| 17 | 16777219 |
| 18 | 38347927 |
| 19 | 214748365 |
| 20 | 214748369 |
| 21 | 4294967297 |
| 22 | 4294967299 |
| 23 | 68719476737 |
| 24 | 68719476769 |
| 25 | 1099511627777 |
| 26 | 4398046511105 |
| 27 | 4398046511109 |