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 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 24 |
| 5 | 82 |
| 6 | 297 |
| 7 | 1121 |
| 8 | 4317 |
| 9 | 16900 |
| 10 | 67185 |
| 11 | 270480 |
| 12 | 1100122 |
| 13 | 4513809 |
| 14 | 18661618 |
| 15 | 77666327 |
| 16 | 325117967 |
| 17 | 1368001765 |
| 18 | 5782686120 |
| 19 | 24545144206 |
| 20 | 104573104040 |
| 21 | 447036252525 |
| 22 | 1916918691196 |
| 23 | 8243075111450 |
| 24 | 35538551601880 |
| 25 | 153584392913986 |
| 26 | 665201585797986 |
| 27 | 2887012910233897 |