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 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 15 |
| 6 | 44 |
| 7 | 140 |
| 8 | 442 |
| 9 | 1443 |
| 10 | 4751 |
| 11 | 15903 |
| 12 | 53716 |
| 13 | 183334 |
| 14 | 630513 |
| 15 | 2184417 |
| 16 | 7614318 |
| 17 | 26690344 |
| 18 | 94015908 |
| 19 | 332639104 |
| 20 | 1181596784 |
| 21 | 4212424485 |
| 22 | 15066677338 |
| 23 | 54050993664 |
| 24 | 194438337125 |
| 25 | 701224890628 |
| 26 | 2534810109024 |