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 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 5 |
| 4 | 20 |
| 5 | 21 |
| 6 | 84 |
| 7 | 85 |
| 8 | 340 |
| 9 | 341 |
| 10 | 1364 |
| 11 | 1365 |
| 12 | 5460 |
| 13 | 5461 |
| 14 | 21844 |
| 15 | 21845 |
| 16 | 87380 |
| 17 | 87381 |
| 18 | 349524 |
| 19 | 349525 |
| 20 | 1398100 |
| 21 | 1398101 |
| 22 | 5592404 |
| 23 | 5592405 |
| 24 | 22369620 |
| 25 | 22369621 |
| 26 | 89478484 |
| 27 | 89478485 |
| 28 | 357913940 |
| 29 | 357913941 |
| 30 | 1431655764 |
| 31 | 1431655765 |
| 32 | 5726623060 |