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 | 5 |
| 3 | 9 |
| 4 | 15 |
| 5 | 33 |
| 6 | 63 |
| 7 | 255 |
| 8 | 513 |
| 9 | 16383 |
| 10 | 131073 |
| 11 | 262143 |
| 12 | 1048575 |
| 13 | 4294967295 |
| 14 | 4611686018427387903 |
| 15 | 1237940039285380274899124223 |
| 16 | 324518553658426726783156020576255 |
| 17 | 340282366920938463463374607431768211455 |