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 | 9 |
| 2 | 21 |
| 3 | 49 |
| 4 | 93 |
| 5 | 217 |
| 6 | 381 |
| 7 | 889 |
| 8 | 961 |
| 9 | 3937 |
| 10 | 16129 |
| 11 | 24573 |
| 12 | 57337 |
| 13 | 253921 |
| 14 | 393213 |
| 15 | 917497 |
| 16 | 1040257 |
| 17 | 1572861 |
| 18 | 3670009 |
| 19 | 4063201 |
| 20 | 16252897 |
| 21 | 16646017 |
| 22 | 66584449 |
| 23 | 67092481 |
| 24 | 1073602561 |
| 25 | 4294434817 |
| 26 | 6442450941 |
| 27 | 15032385529 |
| 28 | 17179607041 |