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 | 4 |
| 2 | 13 |
| 3 | 34 |
| 4 | 79 |
| 5 | 172 |
| 6 | 361 |
| 7 | 742 |
| 8 | 1507 |
| 9 | 3040 |
| 10 | 6109 |
| 11 | 12250 |
| 12 | 24535 |
| 13 | 49108 |
| 14 | 98257 |
| 15 | 196558 |
| 16 | 393163 |
| 17 | 786376 |
| 18 | 1572805 |
| 19 | 3145666 |
| 20 | 6291391 |
| 21 | 12582844 |
| 22 | 25165753 |
| 23 | 50331574 |
| 24 | 100663219 |
| 25 | 201326512 |
| 26 | 402653101 |
| 27 | 805306282 |
| 28 | 1610612647 |
| 29 | 3221225380 |
| 30 | 6442450849 |
| 31 | 12884901790 |