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 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 26 |
| 5 | 169 |
| 6 | 1329 |
| 7 | 12088 |
| 8 | 124221 |
| 9 | 1422307 |
| 10 | 17947550 |
| 11 | 247318851 |
| 12 | 3693469273 |
| 13 | 59396067080 |
| 14 | 1022975862713 |
| 15 | 18781241965081 |
| 16 | 366070181352802 |
| 17 | 7547972562003093 |
| 18 | 164113696105503057 |
| 19 | 3752143293971556144 |
| 20 | 89976991297720804061 |
| 21 | 2257905394760969948079 |