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 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 17 |
| 5 | 65 |
| 6 | 257 |
| 7 | 1025 |
| 8 | 4097 |
| 9 | 16385 |
| 10 | 65537 |
| 11 | 262145 |
| 12 | 1048577 |
| 13 | 4194305 |
| 14 | 16777217 |
| 15 | 67108865 |
| 16 | 268435457 |
| 17 | 1073741825 |
| 18 | 4294967297 |