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 | 3 |
| 2 | 9 |
| 3 | 25 |
| 4 | 65 |
| 5 | 161 |
| 6 | 385 |
| 7 | 897 |
| 8 | 2049 |
| 9 | 4609 |
| 10 | 10241 |
| 11 | 22529 |
| 12 | 49153 |
| 13 | 106497 |
| 14 | 229377 |
| 15 | 491521 |
| 16 | 1048577 |
| 17 | 2228225 |
| 18 | 4718593 |
| 19 | 9961473 |
| 20 | 20971521 |
| 21 | 44040193 |
| 22 | 92274689 |
| 23 | 192937985 |
| 24 | 402653185 |
| 25 | 838860801 |
| 26 | 1744830465 |
| 27 | 3623878657 |
| 28 | 7516192769 |
| 29 | 15569256449 |
| 30 | 32212254721 |
| 31 | 66571993089 |