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) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 21 |
| 3 | 91 |
| 4 | 371 |
| 5 | 1547 |
| 6 | 6405 |
| 7 | 26585 |
| 8 | 110254 |
| 9 | 457379 |
| 10 | 1897214 |
| 11 | 7869927 |
| 12 | 32645269 |
| 13 | 135416457 |
| 14 | 561722840 |
| 15 | 2330091144 |
| 16 | 9665485440 |
| 17 | 40093544735 |
| 18 | 166312629795 |
| 19 | 689883899612 |
| 20 | 2861717685450 |
| 21 | 11870733787751 |
| 22 | 49241167758705 |
| 23 | 204258021937291 |
| 24 | 847285745315256 |