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 | 2 |
| 3 | 2 |
| 4 | 10 |
| 5 | 28 |
| 6 | 207 |
| 7 | 1288 |
| 8 | 10366 |
| 9 | 91296 |
| 10 | 903037 |
| 11 | 9832848 |
| 12 | 117032570 |
| 13 | 1510932116 |
| 14 | 21028774738 |
| 15 | 313832463386 |
| 16 | 4999133311044 |
| 17 | 84655108256252 |
| 18 | 1518546437350265 |
| 19 | 28763765236019284 |
| 20 | 573689119174695326 |
| 21 | 12017485839703597024 |
| 22 | 263787711208968183879 |
| 23 | 6054632852404055079936 |