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 | 3 |
| 4 | 10 |
| 5 | 28 |
| 6 | 76 |
| 7 | 213 |
| 8 | 645 |
| 9 | 1852 |
| 10 | 5642 |
| 11 | 17016 |
| 12 | 51810 |
| 13 | 158290 |
| 14 | 484347 |
| 15 | 1484262 |
| 16 | 4552873 |
| 17 | 13976949 |
| 18 | 42918852 |
| 19 | 131843755 |
| 20 | 405082273 |
| 21 | 1244758709 |
| 22 | 3825355448 |
| 23 | 11756644688 |
| 24 | 36133929611 |
| 25 | 111060564589 |
| 26 | 341360933527 |
| 27 | 1049237831619 |