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 | 1 |
| 1 | 5 |
| 2 | 15 |
| 3 | 37 |
| 4 | 83 |
| 5 | 177 |
| 6 | 367 |
| 7 | 749 |
| 8 | 1515 |
| 9 | 3049 |
| 10 | 6119 |
| 11 | 12261 |
| 12 | 24547 |
| 13 | 49121 |
| 14 | 98271 |
| 15 | 196573 |
| 16 | 393179 |
| 17 | 786393 |
| 18 | 1572823 |
| 19 | 3145685 |
| 20 | 6291411 |
| 21 | 12582865 |
| 22 | 25165775 |
| 23 | 50331597 |
| 24 | 100663243 |
| 25 | 201326537 |
| 26 | 402653127 |
| 27 | 805306309 |
| 28 | 1610612675 |
| 29 | 3221225409 |
| 30 | 6442450879 |
| 31 | 12884901821 |