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 | 2 |
| 2 | 6 |
| 3 | 21 |
| 4 | 73 |
| 5 | 261 |
| 6 | 957 |
| 7 | 3547 |
| 8 | 13267 |
| 9 | 50027 |
| 10 | 189780 |
| 11 | 723456 |
| 12 | 2769333 |
| 13 | 10637790 |
| 14 | 40984228 |
| 15 | 158306891 |
| 16 | 612856611 |
| 17 | 2377260192 |
| 18 | 9237543329 |
| 19 | 35951472496 |
| 20 | 140116098727 |
| 21 | 546778366195 |
| 22 | 2136168391753 |
| 23 | 8354417782742 |
| 24 | 32705042089703 |