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) |
|---|---|
| 3 | 1 |
| 4 | 9 |
| 5 | 55 |
| 6 | 287 |
| 7 | 1381 |
| 8 | 6343 |
| 9 | 28313 |
| 10 | 124083 |
| 11 | 537242 |
| 12 | 2307118 |
| 13 | 9852240 |
| 14 | 41910428 |
| 15 | 177807902 |
| 16 | 752981956 |
| 17 | 3184773246 |
| 18 | 13459063660 |
| 19 | 56849094136 |
| 20 | 240047748038 |
| 21 | 1013452871316 |
| 22 | 4278470305930 |
| 23 | 18062827159136 |
| 24 | 76263743441314 |
| 25 | 322033566728056 |