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 | 11 |
| 2 | 23 |
| 3 | 71 |
| 4 | 263 |
| 5 | 1031 |
| 6 | 65543 |
| 7 | 262151 |
| 8 | 1048583 |
| 9 | 268435463 |
| 10 | 1073741831 |
| 11 | 274877906951 |
| 12 | 17592186044423 |
| 13 | 302231454903657293676551 |
| 14 | 309485009821345068724781063 |
| 15 | 316912650057057350374175801351 |