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 | 0 |
| 2 | 2 |
| 3 | 2 |
| 4 | 8 |
| 5 | 22 |
| 6 | 68 |
| 7 | 212 |
| 8 | 652 |
| 9 | 2017 |
| 10 | 6225 |
| 11 | 19229 |
| 12 | 59393 |
| 13 | 183451 |
| 14 | 566633 |
| 15 | 1750167 |
| 16 | 5405795 |
| 17 | 16697038 |
| 18 | 51572664 |
| 19 | 159294072 |
| 20 | 492016422 |
| 21 | 1519706056 |
| 22 | 4693962286 |
| 23 | 14498384074 |
| 24 | 44781599826 |
| 25 | 138318289075 |
| 26 | 427227905079 |
| 27 | 1319591820767 |