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 | 10101 |
| 2 | 101010 |
| 3 | 111111 |
| 4 | 1010100 |
| 5 | 1010101 |
| 6 | 1111110 |
| 7 | 1111111 |
| 8 | 10101000 |
| 9 | 10101010 |
| 10 | 10111101 |
| 11 | 10111111 |
| 12 | 11111100 |
| 13 | 11111101 |
| 14 | 11111110 |
| 15 | 11111111 |
| 16 | 101010000 |
| 17 | 101010100 |
| 18 | 101010101 |
| 19 | 101111010 |
| 20 | 101111110 |
| 21 | 101111111 |