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 | 9 |
| 1 | 18 |
| 2 | 36 |
| 3 | 72 |
| 4 | 144 |
| 5 | 288 |
| 6 | 576 |
| 7 | 1152 |
| 8 | 2304 |
| 9 | 4608 |
| 10 | 9216 |
| 11 | 18432 |
| 12 | 36864 |
| 13 | 73728 |
| 14 | 147456 |
| 15 | 294912 |
| 16 | 589824 |
| 17 | 1179648 |
| 18 | 2359296 |
| 19 | 4718592 |
| 20 | 9437184 |
| 21 | 18874368 |
| 22 | 37748736 |
| 23 | 75497472 |
| 24 | 150994944 |
| 25 | 301989888 |
| 26 | 603979776 |
| 27 | 1207959552 |
| 28 | 2415919104 |
| 29 | 4831838208 |
| 30 | 9663676416 |
| 31 | 19327352832 |