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 | 7 |
| 2 | 31 |
| 3 | 511 |
| 4 | 8191 |
| 5 | 2097151 |
| 6 | 33554431 |
| 7 | 8589934591 |
| 8 | 137438953471 |
| 9 | 35184372088831 |
| 10 | 144115188075855871 |
| 11 | 2305843009213693951 |
| 12 | 9444732965739290427391 |
| 13 | 2417851639229258349412351 |
| 14 | 38685626227668133590597631 |