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) |
|---|---|
| 0 | 8 |
| 1 | 9 |
| 2 | 11 |
| 3 | 15 |
| 4 | 23 |
| 5 | 39 |
| 6 | 71 |
| 7 | 135 |
| 8 | 263 |
| 9 | 519 |
| 10 | 1031 |
| 11 | 2055 |
| 12 | 4103 |
| 13 | 8199 |
| 14 | 16391 |
| 15 | 32775 |
| 16 | 65543 |
| 17 | 131079 |
| 18 | 262151 |
| 19 | 524295 |
| 20 | 1048583 |
| 21 | 2097159 |
| 22 | 4194311 |
| 23 | 8388615 |
| 24 | 16777223 |
| 25 | 33554439 |
| 26 | 67108871 |
| 27 | 134217735 |
| 28 | 268435463 |
| 29 | 536870919 |
| 30 | 1073741831 |
| 31 | 2147483655 |