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 | 5 |
| 3 | 20 |
| 4 | 83 |
| 5 | 342 |
| 6 | 1411 |
| 7 | 5820 |
| 8 | 24007 |
| 9 | 99026 |
| 10 | 408471 |
| 11 | 1684896 |
| 12 | 6950003 |
| 13 | 28667966 |
| 14 | 118252075 |
| 15 | 487776260 |
| 16 | 2012021183 |
| 17 | 8299356842 |
| 18 | 34233896031 |
| 19 | 141210898600 |
| 20 | 582478776747 |
| 21 | 2402658213526 |
| 22 | 9910689833651 |
| 23 | 40880459994636 |
| 24 | 168627213385143 |