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 | 13 |
| 3 | 19 |
| 4 | 61 |
| 5 | 67 |
| 6 | 1021 |
| 7 | 4093 |
| 8 | 4099 |
| 9 | 16381 |
| 10 | 65539 |
| 11 | 262147 |
| 12 | 1048573 |
| 13 | 4194301 |
| 14 | 16777213 |
| 15 | 268435459 |
| 16 | 1073741827 |
| 17 | 19342813113834066795298819 |
| 18 | 19807040628566084398385987581 |
| 19 | 83076749736557242056487941267521533 |
| 20 | 5316911983139663491615228241121378301 |
| 21 | 1427247692705959881058285969449495136382746621 |