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 | 3 |
| 3 | 6 |
| 4 | 19 |
| 5 | 51 |
| 6 | 157 |
| 7 | 465 |
| 8 | 1444 |
| 9 | 4492 |
| 10 | 14236 |
| 11 | 45097 |
| 12 | 143753 |
| 13 | 458400 |
| 14 | 1464997 |
| 15 | 4682469 |
| 16 | 14970906 |
| 17 | 47834908 |
| 18 | 152721958 |
| 19 | 486927066 |
| 20 | 1549733096 |
| 21 | 4920704208 |
| 22 | 15579074400 |