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 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 16 |
| 5 | 32 |
| 6 | 64 |
| 7 | 128 |
| 8 | 256 |
| 9 | 512 |
| 10 | 2 |
| 11 | 6 |
| 12 | 18 |
| 13 | 54 |
| 14 | 162 |
| 15 | 486 |
| 16 | 1458 |
| 17 | 4374 |
| 18 | 13122 |
| 19 | 39366 |
| 20 | 4 |