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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 8 |
| 5 | 17 |
| 6 | 39 |
| 7 | 97 |
| 8 | 261 |
| 9 | 756 |
| 10 | 2343 |
| 11 | 7722 |
| 12 | 26917 |
| 13 | 98789 |
| 14 | 380360 |
| 15 | 1531698 |
| 16 | 6434385 |
| 17 | 28130890 |
| 18 | 127729730 |
| 19 | 601196428 |
| 20 | 2928369917 |
| 21 | 14738842361 |
| 22 | 76547694741 |
| 23 | 409718539681 |
| 24 | 2257459567236 |
| 25 | 12789959138943 |
| 26 | 74439150889080 |
| 27 | 444647798089245 |
| 28 | 2723583835351855 |