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 | 9 |
| 2 | 54 |
| 3 | 255 |
| 4 | 1035 |
| 5 | 3753 |
| 6 | 12483 |
| 7 | 38701 |
| 8 | 113193 |
| 9 | 315013 |
| 10 | 839802 |
| 11 | 2155905 |
| 12 | 5352252 |
| 13 | 12894426 |
| 14 | 30233558 |
| 15 | 69160869 |
| 16 | 154677325 |
| 17 | 338822547 |
| 18 | 728084435 |
| 19 | 1536931932 |
| 20 | 3190959918 |
| 21 | 6523084815 |
| 22 | 13142291319 |
| 23 | 26118847655 |
| 24 | 51244059231 |
| 25 | 99322878506 |
| 26 | 190306301025 |