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 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 15 |
| 6 | 49 |
| 7 | 168 |
| 8 | 594 |
| 9 | 2150 |
| 10 | 7931 |
| 11 | 29718 |
| 12 | 112814 |
| 13 | 432957 |
| 14 | 1677050 |
| 15 | 6547856 |
| 16 | 25742454 |
| 17 | 101819100 |
| 18 | 404885630 |
| 19 | 1617725010 |
| 20 | 6491294600 |
| 21 | 26147434885 |
| 22 | 105691660110 |
| 23 | 428578242900 |
| 24 | 1742925259725 |
| 25 | 7106942278683 |
| 26 | 29050303230234 |
| 27 | 119014903102956 |
| 28 | 488610373729868 |