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 | 4 |
| 4 | 10 |
| 5 | 26 |
| 6 | 76 |
| 7 | 232 |
| 8 | 764 |
| 9 | 2388 |
| 10 | 7280 |
| 11 | 21574 |
| 12 | 63162 |
| 13 | 183286 |
| 14 | 531576 |
| 15 | 1545583 |
| 16 | 4523049 |
| 17 | 13283748 |
| 18 | 39091824 |
| 19 | 115105436 |
| 20 | 338866164 |
| 21 | 996931680 |
| 22 | 2930722336 |
| 23 | 8610252768 |
| 24 | 25290067376 |
| 25 | 74279609504 |
| 26 | 218185834860 |
| 27 | 640968565724 |
| 28 | 1883199406468 |
| 29 | 5533359251576 |