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) |
|---|---|
| 2 | 1 |
| 3 | 9 |
| 4 | 37 |
| 5 | 147 |
| 6 | 576 |
| 7 | 2244 |
| 8 | 8723 |
| 9 | 33891 |
| 10 | 131716 |
| 11 | 512278 |
| 12 | 1994202 |
| 13 | 7770734 |
| 14 | 30310320 |
| 15 | 118343970 |
| 16 | 462501135 |
| 17 | 1809134115 |
| 18 | 7082699580 |
| 19 | 27750808470 |
| 20 | 108812919270 |
| 21 | 426966196410 |
| 22 | 1676471166240 |
| 23 | 6586744582080 |
| 24 | 25894139638302 |
| 25 | 101852815940622 |
| 26 | 400840469986376 |
| 27 | 1578280410414204 |