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) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 21 |
| 4 | 71 |
| 5 | 216 |
| 6 | 672 |
| 7 | 1982 |
| 8 | 5817 |
| 9 | 16582 |
| 10 | 46633 |
| 11 | 128704 |
| 12 | 350665 |
| 13 | 941715 |
| 14 | 2499640 |
| 15 | 6557378 |
| 16 | 17024095 |
| 17 | 43756166 |
| 18 | 111433472 |
| 19 | 281303882 |
| 20 | 704320180 |
| 21 | 1749727370 |
| 22 | 4314842893 |
| 23 | 10565857064 |
| 24 | 25700414815 |
| 25 | 62115621317 |
| 26 | 149214574760 |
| 27 | 356354881511 |
| 28 | 846292135184 |