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 | 9 |
| 2 | 36 |
| 3 | 117 |
| 4 | 360 |
| 5 | 1089 |
| 6 | 3276 |
| 7 | 9837 |
| 8 | 29520 |
| 9 | 88569 |
| 10 | 265716 |
| 11 | 797157 |
| 12 | 2391480 |
| 13 | 7174449 |
| 14 | 21523356 |
| 15 | 64570077 |
| 16 | 193710240 |
| 17 | 581130729 |
| 18 | 1743392196 |
| 19 | 5230176597 |
| 20 | 15690529800 |
| 21 | 47071589409 |
| 22 | 141214768236 |
| 23 | 423644304717 |
| 24 | 1270932914160 |