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 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 21 |
| 5 | 84 |
| 6 | 214 |
| 7 | 895 |
| 8 | 2607 |
| 9 | 9591 |
| 10 | 31134 |
| 11 | 119313 |
| 12 | 400950 |
| 13 | 1574123 |
| 14 | 5706112 |
| 15 | 22572991 |
| 16 | 86933012 |
| 17 | 356058243 |
| 18 | 1427784135 |
| 19 | 6044132304 |
| 20 | 25342935667 |
| 21 | 110414556330 |
| 22 | 481712291885 |
| 23 | 2166488898387 |
| 24 | 9784077216457 |
| 25 | 45369658599779 |
| 26 | 211869746691055 |
| 27 | 1011161497851296 |
| 28 | 4871413403219085 |