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 | 3 |
| 2 | 9 |
| 3 | 28 |
| 4 | 84 |
| 5 | 252 |
| 6 | 758 |
| 7 | 2274 |
| 8 | 6822 |
| 9 | 20471 |
| 10 | 61413 |
| 11 | 184239 |
| 12 | 552729 |
| 13 | 1658187 |
| 14 | 4974561 |
| 15 | 14923714 |
| 16 | 44771142 |
| 17 | 134313426 |
| 18 | 402940361 |
| 19 | 1208821083 |
| 20 | 3626463249 |
| 21 | 10879389971 |
| 22 | 32638169913 |
| 23 | 97914509739 |
| 24 | 293743529832 |
| 25 | 881230589496 |
| 26 | 2643691768488 |
| 27 | 7931075307172 |