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 | 3 |
| 1 | 7 |
| 2 | 18 |
| 3 | 50 |
| 4 | 145 |
| 5 | 429 |
| 6 | 1280 |
| 7 | 3832 |
| 8 | 11487 |
| 9 | 34451 |
| 10 | 103342 |
| 11 | 310014 |
| 12 | 930029 |
| 13 | 2790073 |
| 14 | 8370204 |
| 15 | 25110596 |
| 16 | 75331771 |
| 17 | 225995295 |
| 18 | 677985866 |
| 19 | 2033957578 |
| 20 | 6101872713 |
| 21 | 18305618117 |
| 22 | 54916854328 |
| 23 | 164750562960 |
| 24 | 494251688855 |
| 25 | 1482755066539 |