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 | 1 |
| 3 | 4 |
| 4 | 6 |
| 5 | 19 |
| 6 | 49 |
| 7 | 143 |
| 8 | 403 |
| 9 | 1235 |
| 10 | 3681 |
| 11 | 11354 |
| 12 | 34944 |
| 13 | 108956 |
| 14 | 340635 |
| 15 | 1072593 |
| 16 | 3388161 |
| 17 | 10751029 |
| 18 | 34217608 |
| 19 | 109255023 |
| 20 | 349750874 |
| 21 | 1122436127 |
| 22 | 3610017340 |