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 | 3 |
| 2 | 9 |
| 3 | 42 |
| 4 | 178 |
| 5 | 910 |
| 6 | 4212 |
| 7 | 19899 |
| 8 | 94217 |
| 9 | 445859 |
| 10 | 2113257 |
| 11 | 10006598 |
| 12 | 47387904 |
| 13 | 224418390 |
| 14 | 1062810762 |
| 15 | 5033385029 |
| 16 | 23837475807 |
| 17 | 112891241315 |
| 18 | 534638647159 |
| 19 | 2531982065694 |
| 20 | 11991154349342 |
| 21 | 56788620500294 |
| 22 | 268943860673076 |