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 | 2 |
| 3 | 3 |
| 4 | 7 |
| 5 | 15 |
| 6 | 36 |
| 7 | 85 |
| 8 | 211 |
| 9 | 525 |
| 10 | 1341 |
| 11 | 3449 |
| 12 | 9001 |
| 13 | 23671 |
| 14 | 62835 |
| 15 | 167881 |
| 16 | 451557 |
| 17 | 1221065 |
| 18 | 3318737 |
| 19 | 9059397 |
| 20 | 24830110 |
| 21 | 68299159 |
| 22 | 188488448 |
| 23 | 521737636 |
| 24 | 1448154837 |
| 25 | 4029712400 |
| 26 | 11239492056 |
| 27 | 31416403198 |
| 28 | 87990722479 |
| 29 | 246903542031 |
| 30 | 694022911203 |
| 31 | 1954012196966 |