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 | 3 |
| 3 | 9 |
| 4 | 28 |
| 5 | 84 |
| 6 | 252 |
| 7 | 757 |
| 8 | 2271 |
| 9 | 6813 |
| 10 | 20440 |
| 11 | 61320 |
| 12 | 183960 |
| 13 | 551881 |
| 14 | 1655643 |
| 15 | 4966929 |
| 16 | 14900788 |
| 17 | 44702364 |
| 18 | 134107092 |
| 19 | 402321277 |
| 20 | 1206963831 |
| 21 | 3620891493 |
| 22 | 10862674480 |
| 23 | 32588023440 |
| 24 | 97764070320 |
| 25 | 293292210961 |
| 26 | 879876632883 |