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 | 0 |
| 1 | 3 |
| 2 | 12 |
| 3 | 33 |
| 4 | 96 |
| 5 | 255 |
| 6 | 780 |
| 7 | 2205 |
| 8 | 6672 |
| 9 | 19755 |
| 10 | 59340 |
| 11 | 177177 |
| 12 | 532416 |
| 13 | 1594359 |
| 14 | 4785228 |
| 15 | 14349525 |
| 16 | 43053504 |
| 17 | 129140211 |
| 18 | 387441756 |
| 19 | 1162261521 |
| 20 | 3486844320 |
| 21 | 10460357775 |
| 22 | 31381236876 |
| 23 | 94143178893 |
| 24 | 282430082832 |
| 25 | 847288610475 |